fix(migrations): re-chain mobile devices migration against main and restore merge conflicts

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

app/api/__init__.py

@@ -8,6 +8,7 @@ from fastapi import APIRouter
 
 from app.api.admin_users import router as admin_users_router
 from app.api.api_tokens import router as api_tokens_router
+from app.api.audit_logs import router as audit_logs_router
 from app.api.azure import router as azure_router
 from app.api.backup import router as backup_router
 from app.api.billing import router as billing_router
@@ -17,6 +18,7 @@ from app.api.dropbox import router as dropbox_router
 from app.api.duplicates import router as duplicates_router
 from app.api.files import router as files_router
 from app.api.google_drive import router as google_drive_router
+from app.api.i18n import router as i18n_router
 from app.api.imap_accounts import router as imap_accounts_router
 from app.api.integrations import router as integrations_router
 from app.api.logs import router as logs_router
@@ -83,4 +85,6 @@ router.include_router(imap_accounts_router)
 router.include_router(integrations_router)
 router.include_router(notifications_router)
 router.include_router(scheduled_jobs_router)
+router.include_router(audit_logs_router)
+router.include_router(i18n_router)
 router.include_router(mobile_router)

app/api/audit_logs.py

@@ -0,0 +1,115 @@
+"""
+Audit log REST API endpoints.
+
+Provides read-only access to the comprehensive audit log for admin users.
+Events are append-only — there are no update or delete endpoints.
+"""
+
+import logging
+from datetime import datetime
+from typing import Any
+
+from fastapi import APIRouter, Depends, Query, Request
+from sqlalchemy.orm import Session
+
+from app.auth import require_login
+from app.database import get_db
+from app.utils.audit_service import count_events, query_events
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter()
+
+
+@router.get("/audit-logs")
+@require_login
+async def list_audit_logs(
+    request: Request,
+    db: Session = Depends(get_db),
+    action: str | None = Query(None, description="Filter by action (exact match)"),
+    user: str | None = Query(None, description="Filter by username"),
+    resource_type: str | None = Query(None, description="Filter by resource type"),
+    severity: str | None = Query(None, description="Filter by severity level"),
+    since: datetime | None = Query(None, description="Only events at or after this ISO-8601 timestamp"),
+    until: datetime | None = Query(None, description="Only events at or before this ISO-8601 timestamp"),
+    limit: int = Query(50, ge=1, le=500, description="Max rows to return"),
+    offset: int = Query(0, ge=0, description="Rows to skip for pagination"),
+) -> dict[str, Any]:
+    """Return audit log entries with optional filtering and pagination.
+
+    Requires authentication. Returns events in reverse chronological order.
+    """
+    entries = query_events(
+        db,
+        action=action,
+        user=user,
+        resource_type=resource_type,
+        severity=severity,
+        since=since,
+        until=until,
+        limit=limit,
+        offset=offset,
+    )
+    total = count_events(
+        db,
+        action=action,
+        user=user,
+        resource_type=resource_type,
+        severity=severity,
+        since=since,
+        until=until,
+    )
+    return {
+        "items": [_serialize(e) for e in entries],
+        "total": total,
+        "limit": limit,
+        "offset": offset,
+    }
+
+
+@router.get("/audit-logs/actions")
+@require_login
+async def list_distinct_actions(
+    request: Request,
+    db: Session = Depends(get_db),
+) -> list[str]:
+    """Return the distinct action values present in the audit log."""
+    from app.models import AuditLog
+
+    rows = db.query(AuditLog.action).distinct().order_by(AuditLog.action).all()
+    return [r[0] for r in rows]
+
+
+@router.get("/audit-logs/users")
+@require_login
+async def list_distinct_users(
+    request: Request,
+    db: Session = Depends(get_db),
+) -> list[str]:
+    """Return the distinct user values present in the audit log."""
+    from app.models import AuditLog
+
+    rows = db.query(AuditLog.user).distinct().order_by(AuditLog.user).all()
+    return [r[0] for r in rows]
+
+
+# ------------------------------------------------------------------
+# Helpers
+# ------------------------------------------------------------------
+
+
+def _serialize(entry) -> dict[str, Any]:
+    """Convert an AuditLog row to a JSON-safe dict."""
+    import json as _json
+
+    return {
+        "id": entry.id,
+        "timestamp": entry.timestamp.isoformat() if entry.timestamp else None,
+        "user": entry.user,
+        "action": entry.action,
+        "resource_type": entry.resource_type,
+        "resource_id": entry.resource_id,
+        "ip_address": entry.ip_address,
+        "details": _json.loads(entry.details) if entry.details else None,
+        "severity": entry.severity,
+    }

app/api/i18n.py

@@ -0,0 +1,136 @@
+"""API endpoints for internationalization (i18n).
+
+Provides endpoints for:
+* Listing available languages
+* Getting/setting user language preference (persisted in session + cookie + DB)
+"""
+
+from __future__ import annotations
+
+import logging
+
+from fastapi import APIRouter, Depends, Request, Response
+from pydantic import BaseModel
+from sqlalchemy.orm import Session
+
+from app.database import get_db
+from app.models import UserProfile
+from app.utils.i18n import (
+    DEFAULT_LANGUAGE,
+    SUPPORTED_LANGUAGE_CODES,
+    SUPPORTED_LANGUAGES,
+    detect_language,
+)
+
+logger = logging.getLogger(__name__)
+
+router = APIRouter(prefix="/i18n", tags=["i18n"])
+
+
+class LanguageInfo(BaseModel):
+    """Schema for a supported language."""
+
+    code: str
+    name: str
+    native: str
+    flag: str
+
+
+class LanguageListResponse(BaseModel):
+    """Response for the list-languages endpoint."""
+
+    languages: list[LanguageInfo]
+    current: str
+    default: str
+
+
+class SetLanguageRequest(BaseModel):
+    """Request body for setting the preferred language."""
+
+    language: str
+
+
+class SetLanguageResponse(BaseModel):
+    """Response after changing the language."""
+
+    language: str
+    message: str
+
+
+@router.get("/languages", response_model=LanguageListResponse)
+async def list_languages(request: Request) -> LanguageListResponse:
+    """Return all supported UI languages and the current active language."""
+    current = detect_language(request)
+    return LanguageListResponse(
+        languages=[LanguageInfo(**lang) for lang in SUPPORTED_LANGUAGES],
+        current=current,
+        default=DEFAULT_LANGUAGE,
+    )
+
+
+@router.post("/language", response_model=SetLanguageResponse)
+async def set_language(
+    body: SetLanguageRequest,
+    request: Request,
+    response: Response,
+    db: Session = Depends(get_db),
+) -> SetLanguageResponse:
+    """Set the preferred UI language.
+
+    Persists the choice in:
+    1. The server-side session
+    2. A ``docuelevate_lang`` cookie (30-day expiry)
+    3. The ``UserProfile.preferred_language`` column (if authenticated)
+    """
+    lang = body.language.lower().strip()
+    if lang not in SUPPORTED_LANGUAGE_CODES:
+        lang = DEFAULT_LANGUAGE
+
+    # 1. Session
+    if hasattr(request, "session"):
+        request.session["preferred_language"] = lang
+
+    # 2. Cookie (30 days)
+    response.set_cookie(
+        key="docuelevate_lang",
+        value=lang,
+        max_age=30 * 24 * 60 * 60,
+        httponly=False,
+        samesite="lax",
+    )
+
+    # 3. Database (if user is authenticated)
+    _persist_language_to_profile(request, db, lang)
+
+    language_name = next(
+        (entry["native"] for entry in SUPPORTED_LANGUAGES if entry["code"] == lang),
+        lang,
+    )
+    logger.info("Language preference set to '%s'", lang)
+    return SetLanguageResponse(
+        language=lang,
+        message=f"Language changed to {language_name}",
+    )
+
+
+def _persist_language_to_profile(request: Request, db: Session, lang: str) -> None:
+    """Write language preference to the UserProfile row, if the user is logged in."""
+    user_id: str | None = None
+    if hasattr(request, "session"):
+        user = request.session.get("user")
+        if isinstance(user, dict):
+            user_id = user.get("preferred_username") or user.get("email") or user.get("id")
+        elif isinstance(user, str):
+            user_id = user
+
+    if not user_id:
+        return
+
+    try:
+        profile = db.query(UserProfile).filter(UserProfile.user_id == user_id).first()
+        if profile:
+            profile.preferred_language = lang  # type: ignore[attr-defined]
+            db.commit()
+    except Exception:
+        db.rollback()
+        logger.debug("Could not persist language preference for user_id=%s", user_id)

app/config.py

@@ -849,6 +849,49 @@ class Settings(BaseSettings):
         ),
     )
 
+    # SIEM / External Audit Log Forwarding
+    # Forward audit events to external SIEM systems for centralised monitoring.
+    audit_siem_enabled: bool = Field(
+        default=False,
+        description="Enable forwarding of audit events to an external SIEM system.",
+    )
+    audit_siem_transport: str = Field(
+        default="syslog",
+        description=(
+            "Transport used to forward audit events. "
+            "Options: 'syslog' (RFC 5424 over UDP/TCP), 'http' (JSON POST to a webhook URL, "
+            "compatible with Splunk HEC, Logstash HTTP input, Grafana Loki, etc.)."
+        ),
+    )
+    audit_siem_syslog_host: str = Field(
+        default="localhost",
+        description="Hostname or IP of the syslog receiver.",
+    )
+    audit_siem_syslog_port: int = Field(
+        default=514,
+        description="Port of the syslog receiver.",
+    )
+    audit_siem_syslog_protocol: str = Field(
+        default="udp",
+        description="Protocol for syslog transport: 'udp' or 'tcp'.",
+    )
+    audit_siem_http_url: str = Field(
+        default="",
+        description=(
+            "HTTP endpoint URL for SIEM webhook delivery. "
+            "Supports Splunk HEC (https://splunk:8088/services/collector/event), "
+            "Logstash HTTP input, Grafana Loki push API, or any JSON-accepting endpoint."
+        ),
+    )
+    audit_siem_http_token: str = Field(
+        default="",
+        description="Bearer / HEC token included in the Authorization header of SIEM HTTP requests.",
+    )
+    audit_siem_http_custom_headers: str = Field(
+        default="",
+        description="Comma-separated 'Key:Value' pairs of extra headers for SIEM HTTP requests.",
+    )
+
     # UI / Appearance
     ui_default_color_scheme: str = Field(
         default="system",

app/models.py

@@ -146,6 +146,27 @@ class SettingsAuditLog(Base):
     action = Column(String, nullable=False)  # "update" or "delete"
 
 
+class AuditLog(Base):
+    """Comprehensive audit log for compliance tracking.
+
+    Records all significant actions: login/logout, document CRUD, settings
+    changes, and administrative operations.  Rows are append-only; the API
+    and service layer never update or delete entries.
+    """
+
+    __tablename__ = "audit_logs"
+
+    id = Column(Integer, primary_key=True, index=True)
+    timestamp = Column(DateTime(timezone=True), server_default=func.now(), nullable=False, index=True)
+    user = Column(String, nullable=False, index=True)  # Username or "anonymous" / "system"
+    action = Column(String, nullable=False, index=True)  # e.g. "login", "document.create", "settings.update"
+    resource_type = Column(String, nullable=True, index=True)  # e.g. "document", "user", "settings"
+    resource_id = Column(String, nullable=True)  # ID of the affected resource
+    ip_address = Column(String, nullable=True)  # Client IP address
+    details = Column(Text, nullable=True)  # JSON-encoded extra context
+    severity = Column(String(16), nullable=False, server_default="info")  # info / warning / error / critical
+
+
 class SavedSearch(Base):
     """User-defined saved search filters for quick access to frequently used filter combinations."""
 
@@ -256,6 +277,10 @@ class UserProfile(Base):
     preferred_destination = Column(String(50), nullable=True)
     stripe_customer_id = Column(String(64), nullable=True)
 
+    # UI language preference for i18n (ISO 639-1 code, e.g. "en", "de", "fr")
+    # NULL means "auto-detect from browser Accept-Language header"
+    preferred_language = Column(String(10), nullable=True)
+
     created_at = Column(DateTime(timezone=True), server_default=func.now())
     updated_at = Column(DateTime(timezone=True), server_default=func.now(), onupdate=func.now())
 

app/utils/audit_service.py

@@ -0,0 +1,331 @@
+"""
+Comprehensive audit-event service for DocuElevate.
+
+Provides helpers to **record** audit events (append-only database writes)
+and to optionally **forward** them to external SIEM systems.
+
+Supported SIEM transports:
+* **Syslog** – RFC 5424 structured-data messages over UDP or TCP.
+* **HTTP** – JSON POST payloads compatible with Splunk HEC, Logstash
+  HTTP input, Grafana Loki push API, and any generic webhook endpoint.
+"""
+
+import json
+import logging
+import re
+import socket
+import threading
+from datetime import datetime, timezone
+from typing import Any
+
+import httpx
+from fastapi import Request
+from sqlalchemy.orm import Session
+
+from app.config import settings
+from app.middleware.audit_log import get_client_ip, get_username
+from app.models import AuditLog
+
+logger = logging.getLogger(__name__)
+
+# ---------------------------------------------------------------------------
+# Public helpers
+# ---------------------------------------------------------------------------
+
+
+def record_event(
+    db: Session,
+    *,
+    action: str,
+    user: str = "system",
+    resource_type: str | None = None,
+    resource_id: str | None = None,
+    ip_address: str | None = None,
+    details: dict[str, Any] | None = None,
+    severity: str = "info",
+) -> AuditLog:
+    """Persist an audit event and optionally forward it to SIEM.
+
+    Args:
+        db: Active SQLAlchemy session.
+        action: Short action identifier (e.g. ``"login"``, ``"document.create"``).
+        user: Username performing the action.
+        resource_type: Category of the affected resource (``"document"``, ``"user"`` …).
+        resource_id: Identifier of the affected resource.
+        ip_address: Client IP address (``None`` when not applicable).
+        details: Arbitrary key/value context serialised as JSON.
+        severity: One of ``info``, ``warning``, ``error``, ``critical``.
+
+    Returns:
+        The newly created :class:`AuditLog` row.
+    """
+    details_json = json.dumps(details, default=str) if details else None
+
+    entry = AuditLog(
+        user=user,
+        action=action,
+        resource_type=resource_type,
+        resource_id=str(resource_id) if resource_id is not None else None,
+        ip_address=ip_address,
+        details=details_json,
+        severity=severity,
+    )
+    db.add(entry)
+    db.commit()
+    db.refresh(entry)
+
+    # Fire-and-forget SIEM forwarding in a background thread so we never
+    # block the request path.
+    if settings.audit_siem_enabled:
+        payload = _build_siem_payload(entry)
+        thread = threading.Thread(target=_forward_to_siem, args=(payload,), daemon=True)
+        thread.start()
+
+    return entry
+
+
+def record_event_from_request(
+    db: Session,
+    request: Request,
+    *,
+    action: str,
+    resource_type: str | None = None,
+    resource_id: str | None = None,
+    details: dict[str, Any] | None = None,
+    severity: str = "info",
+) -> AuditLog:
+    """Convenience wrapper that extracts user and IP from a :class:`Request`.
+
+    Args:
+        db: Active SQLAlchemy session.
+        request: The current HTTP request.
+        action: Short action identifier.
+        resource_type: Category of the affected resource.
+        resource_id: Identifier of the affected resource.
+        details: Arbitrary key/value context serialised as JSON.
+        severity: One of ``info``, ``warning``, ``error``, ``critical``.
+
+    Returns:
+        The newly created :class:`AuditLog` row.
+    """
+    return record_event(
+        db,
+        action=action,
+        user=get_username(request),
+        resource_type=resource_type,
+        resource_id=resource_id,
+        ip_address=get_client_ip(request),
+        details=details,
+        severity=severity,
+    )
+
+
+def query_events(
+    db: Session,
+    *,
+    action: str | None = None,
+    user: str | None = None,
+    resource_type: str | None = None,
+    severity: str | None = None,
+    since: datetime | None = None,
+    until: datetime | None = None,
+    limit: int = 200,
+    offset: int = 0,
+) -> list[AuditLog]:
+    """Query audit log entries with optional filtering.
+
+    Args:
+        db: Active SQLAlchemy session.
+        action: Filter by action string (exact match).
+        user: Filter by username (exact match).
+        resource_type: Filter by resource type (exact match).
+        severity: Filter by severity level (exact match).
+        since: Only events at or after this timestamp.
+        until: Only events at or before this timestamp.
+        limit: Maximum number of rows to return.
+        offset: Number of rows to skip (for pagination).
+
+    Returns:
+        List of :class:`AuditLog` rows ordered by *timestamp descending*.
+    """
+    q = db.query(AuditLog)
+    if action:
+        q = q.filter(AuditLog.action == action)
+    if user:
+        q = q.filter(AuditLog.user == user)
+    if resource_type:
+        q = q.filter(AuditLog.resource_type == resource_type)
+    if severity:
+        q = q.filter(AuditLog.severity == severity)
+    if since:
+        q = q.filter(AuditLog.timestamp >= since)
+    if until:
+        q = q.filter(AuditLog.timestamp <= until)
+    return q.order_by(AuditLog.timestamp.desc()).offset(offset).limit(limit).all()
+
+
+def count_events(
+    db: Session,
+    *,
+    action: str | None = None,
+    user: str | None = None,
+    resource_type: str | None = None,
+    severity: str | None = None,
+    since: datetime | None = None,
+    until: datetime | None = None,
+) -> int:
+    """Return the total count of events matching the given filters.
+
+    Args:
+        db: Active SQLAlchemy session.
+        action: Filter by action string.
+        user: Filter by username.
+        resource_type: Filter by resource type.
+        severity: Filter by severity level.
+        since: Only events at or after this timestamp.
+        until: Only events at or before this timestamp.
+
+    Returns:
+        Integer count.
+    """
+    q = db.query(AuditLog)
+    if action:
+        q = q.filter(AuditLog.action == action)
+    if user:
+        q = q.filter(AuditLog.user == user)
+    if resource_type:
+        q = q.filter(AuditLog.resource_type == resource_type)
+    if severity:
+        q = q.filter(AuditLog.severity == severity)
+    if since:
+        q = q.filter(AuditLog.timestamp >= since)
+    if until:
+        q = q.filter(AuditLog.timestamp <= until)
+    return q.count()
+
+
+# ---------------------------------------------------------------------------
+# SIEM forwarding internals
+# ---------------------------------------------------------------------------
+
+_SYSLOG_FACILITY_LOCAL0 = 16
+_SYSLOG_SEVERITY_MAP = {
+    "info": 6,
+    "warning": 4,
+    "error": 3,
+    "critical": 2,
+}
+
+
+def _build_siem_payload(entry: AuditLog) -> dict[str, Any]:
+    """Convert an :class:`AuditLog` row into a plain dict for SIEM delivery."""
+    ts = entry.timestamp if entry.timestamp else datetime.now(timezone.utc)
+    return {
+        "id": entry.id,
+        "timestamp": ts.isoformat(),
+        "user": entry.user,
+        "action": entry.action,
+        "resource_type": entry.resource_type,
+        "resource_id": entry.resource_id,
+        "ip_address": entry.ip_address,
+        "details": entry.details,
+        "severity": entry.severity,
+        "source": "docuelevate",
+    }
+
+
+def _forward_to_siem(payload: dict[str, Any]) -> None:
+    """Route a SIEM payload to the configured transport."""
+    transport = settings.audit_siem_transport.lower()
+    try:
+        if transport == "syslog":
+            _send_syslog(payload)
+        elif transport == "http":
+            _send_http(payload)
+        else:
+            logger.warning("Unknown SIEM transport %r; skipping forwarding", transport)
+    except Exception:
+        logger.exception("Failed to forward audit event to SIEM (%s)", transport)
+
+
+def _send_syslog(payload: dict[str, Any]) -> None:
+    """Send a RFC 5424 syslog message to the configured receiver."""
+    severity_num = _SYSLOG_SEVERITY_MAP.get(payload.get("severity", "info"), 6)
+    priority = _SYSLOG_FACILITY_LOCAL0 * 8 + severity_num
+    ts = payload.get("timestamp", datetime.now(timezone.utc).isoformat())
+    hostname = socket.gethostname()
+    app_name = "docuelevate"
+    msg_id = payload.get("action", "-")
+
+    # Structured data (SD) element with key event fields.
+    sd = (
+        f'[docuelevate@0 user="{payload.get("user", "-")}" '
+        f'action="{payload.get("action", "-")}" '
+        f'resource_type="{payload.get("resource_type", "-")}" '
+        f'resource_id="{payload.get("resource_id", "-")}" '
+        f'ip="{payload.get("ip_address", "-")}"]'
+    )
+    message = json.dumps(payload, default=str)
+    syslog_msg = f"<{priority}>1 {ts} {hostname} {app_name} - {msg_id} {sd} {message}"
+
+    proto = settings.audit_siem_syslog_protocol.lower()
+    host = settings.audit_siem_syslog_host
+    port = settings.audit_siem_syslog_port
+
+    if proto == "tcp":
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            sock.settimeout(5)
+            sock.connect((host, port))
+            sock.sendall(syslog_msg.encode("utf-8"))
+    else:
+        with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
+            sock.settimeout(5)
+            sock.sendto(syslog_msg.encode("utf-8"), (host, port))
+
+    logger.debug("Syslog audit event sent to %s:%s (%s)", host, port, proto)
+
+
+def _send_http(payload: dict[str, Any]) -> None:
+    """POST a JSON audit event to the configured HTTP endpoint."""
+    url = settings.audit_siem_http_url
+    if not url:
+        logger.warning("SIEM HTTP URL not configured; skipping HTTP forwarding")
+        return
+
+    headers: dict[str, str] = {"Content-Type": "application/json"}
+    token = settings.audit_siem_http_token
+    if token:
+        headers["Authorization"] = f"Bearer {token}"
+
+    # Parse custom headers (comma-separated "Key:Value" pairs).
+    # Reject headers that could override security-critical ones already set,
+    # and validate that header names contain only RFC 7230 token characters.
+    _PROTECTED_HEADERS = {"authorization", "content-type", "host"}
+    _VALID_HEADER_NAME = re.compile(r"^[A-Za-z0-9!#$%&'*+\-.^_`|~]+$")
+    raw_custom = settings.audit_siem_http_custom_headers
+    if raw_custom:
+        for raw_pair in raw_custom.split(","):
+            pair = raw_pair.strip()
+            if ":" in pair:
+                k, _, v = pair.partition(":")
+                name = k.strip()
+                if not name or not _VALID_HEADER_NAME.match(name):
+                    logger.warning("Skipping invalid SIEM custom header name: %r", name)
+                    continue
+                if name.lower() in _PROTECTED_HEADERS:
+                    logger.warning("Skipping protected SIEM custom header: %r", name)
+                    continue
+                headers[name] = v.strip()
+
+    # Wrap in Splunk HEC-style envelope when URL contains ``/services/collector``.
+    body: dict[str, Any]
+    if "/services/collector" in url:
+        body = {"event": payload, "sourcetype": "docuelevate:audit", "source": "docuelevate"}
+    else:
+        body = payload
+
+    with httpx.Client(timeout=10) as client:
+        resp = client.post(url, json=body, headers=headers)
+        resp.raise_for_status()
+
+    logger.debug("HTTP audit event forwarded to %s (status %s)", url, resp.status_code)

app/utils/db_migrate.py

@@ -32,8 +32,10 @@ _TABLE_ORDER = [
     "processing_logs",
     "application_settings",
     "settings_audit_log",
+    "audit_logs",
     "saved_searches",
     "webhook_configs",
+    "shared_links",
 ]
 
 

app/utils/i18n.py

@@ -0,0 +1,539 @@
+"""Internationalization (i18n) and localization (l10n) utilities.
+
+Provides a JSON-based translation system for the DocuElevate UI with:
+
+* **31 supported languages** covering all major European languages plus ZH
+* Browser ``Accept-Language`` detection with cookie & user-profile persistence
+* AI-powered fallback translation via the configured LLM provider
+* Locale-aware date, number, and file-size formatting helpers
+* Jinja2 integration via a ``_()`` global function
+
+Language resolution order:
+    1. User profile ``preferred_language`` (persisted in DB)
+    2. ``docuelevate_lang`` cookie
+    3. ``Accept-Language`` HTTP header
+    4. Default (``en``)
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+from datetime import date, datetime
+from functools import lru_cache
+from pathlib import Path
+from typing import Any
+
+from starlette.requests import Request
+
+logger = logging.getLogger(__name__)
+
+# ---------------------------------------------------------------------------
+# Supported languages (ordered by priority)
+# ---------------------------------------------------------------------------
+
+SUPPORTED_LANGUAGES: list[dict[str, str]] = [
+    # --- Tier 1: Primary European languages ---
+    {"code": "en", "name": "English", "native": "English", "flag": "🇬🇧"},
+    {"code": "de", "name": "German", "native": "Deutsch", "flag": "🇩🇪"},
+    {"code": "fr", "name": "French", "native": "Français", "flag": "🇫🇷"},
+    {"code": "es", "name": "Spanish", "native": "Español", "flag": "🇪🇸"},
+    {"code": "it", "name": "Italian", "native": "Italiano", "flag": "🇮🇹"},
+    {"code": "pt", "name": "Portuguese", "native": "Português", "flag": "🇵🇹"},
+    # --- Tier 2: Western & Northern European ---
+    {"code": "nl", "name": "Dutch", "native": "Nederlands", "flag": "🇳🇱"},
+    {"code": "nb", "name": "Norwegian", "native": "Norsk", "flag": "🇳🇴"},
+    {"code": "da", "name": "Danish", "native": "Dansk", "flag": "🇩🇰"},
+    {"code": "sv", "name": "Swedish", "native": "Svenska", "flag": "🇸🇪"},
+    {"code": "fi", "name": "Finnish", "native": "Suomi", "flag": "🇫🇮"},
+    {"code": "is", "name": "Icelandic", "native": "Íslenska", "flag": "🇮🇸"},
+    {"code": "ga", "name": "Irish", "native": "Gaeilge", "flag": "🇮🇪"},
+    {"code": "lb", "name": "Luxembourgish", "native": "Lëtzebuergesch", "flag": "🇱🇺"},
+    {"code": "ca", "name": "Catalan", "native": "Català", "flag": "🏴"},
+    # --- Tier 3: Central & Eastern European ---
+    {"code": "pl", "name": "Polish", "native": "Polski", "flag": "🇵🇱"},
+    {"code": "cs", "name": "Czech", "native": "Čeština", "flag": "🇨🇿"},
+    {"code": "sk", "name": "Slovak", "native": "Slovenčina", "flag": "🇸🇰"},
+    {"code": "hu", "name": "Hungarian", "native": "Magyar", "flag": "🇭🇺"},
+    {"code": "sl", "name": "Slovenian", "native": "Slovenščina", "flag": "🇸🇮"},
+    {"code": "hr", "name": "Croatian", "native": "Hrvatski", "flag": "🇭🇷"},
+    {"code": "ro", "name": "Romanian", "native": "Română", "flag": "🇷🇴"},
+    {"code": "bg", "name": "Bulgarian", "native": "Български", "flag": "🇧🇬"},
+    {"code": "el", "name": "Greek", "native": "Ελληνικά", "flag": "🇬🇷"},
+    {"code": "et", "name": "Estonian", "native": "Eesti", "flag": "🇪🇪"},
+    {"code": "lv", "name": "Latvian", "native": "Latviešu", "flag": "🇱🇻"},
+    {"code": "lt", "name": "Lithuanian", "native": "Lietuvių", "flag": "🇱🇹"},
+    # --- Tier 4: Non-EU European & Other ---
+    {"code": "tr", "name": "Turkish", "native": "Türkçe", "flag": "🇹🇷"},
+    {"code": "uk", "name": "Ukrainian", "native": "Українська", "flag": "🇺🇦"},
+    {"code": "ru", "name": "Russian", "native": "Русский", "flag": "🇷🇺"},
+    {"code": "zh", "name": "Chinese", "native": "中文", "flag": "🇨🇳"},
+]
+
+SUPPORTED_LANGUAGE_CODES: set[str] = {lang["code"] for lang in SUPPORTED_LANGUAGES}
+DEFAULT_LANGUAGE = "en"
+
+# ---------------------------------------------------------------------------
+# Translation file loading
+# ---------------------------------------------------------------------------
+
+_TRANSLATIONS_DIR = Path(__file__).resolve().parent.parent.parent / "frontend" / "translations"
+_translation_cache: dict[str, dict[str, str]] = {}
+
+
+def _load_translations(locale: str) -> dict[str, str]:
+    """Load the translation JSON file for *locale*, with caching."""
+    if locale in _translation_cache:
+        return _translation_cache[locale]
+
+    filepath = _TRANSLATIONS_DIR / f"{locale}.json"
+    if not filepath.is_file():
+        logger.warning("Translation file not found for locale '%s'", locale)
+        _translation_cache[locale] = {}
+        return {}
+
+    try:
+        data: dict[str, str] = json.loads(filepath.read_text(encoding="utf-8"))
+        _translation_cache[locale] = data
+        return data
+    except (json.JSONDecodeError, OSError):
+        logger.exception("Failed to load translations for '%s'", locale)
+        _translation_cache[locale] = {}
+        return {}
+
+
+def reload_translations() -> None:
+    """Clear the translation cache so files are re-read on next access."""
+    _translation_cache.clear()
+
+
+# ---------------------------------------------------------------------------
+# Core translation function
+# ---------------------------------------------------------------------------
+
+
+def translate(key: str, locale: str | None = None, **kwargs: Any) -> str:
+    """Return the translated string for *key* in *locale*.
+
+    Falls back through:
+        1. Requested *locale*
+        2. English (``en``)
+        3. The raw key itself (to keep the UI functional)
+
+    Positional placeholders ``{0}``, ``{1}`` or named placeholders
+    ``{name}`` in the translated string are interpolated via *kwargs*.
+    """
+    locale = locale if locale and locale in SUPPORTED_LANGUAGE_CODES else DEFAULT_LANGUAGE
+
+    translations = _load_translations(locale)
+    value = translations.get(key)
+
+    # Fallback to English
+    if value is None and locale != DEFAULT_LANGUAGE:
+        en_translations = _load_translations(DEFAULT_LANGUAGE)
+        value = en_translations.get(key)
+
+    # Fallback to key itself
+    if value is None:
+        value = key
+
+    if kwargs:
+        try:
+            value = value.format(**kwargs)
+        except (KeyError, IndexError):
+            pass  # Return unformatted string rather than crash
+
+    return value
+
+
+# ---------------------------------------------------------------------------
+# AI fallback translation (best-effort, non-blocking)
+# ---------------------------------------------------------------------------
+
+_ai_translation_cache: dict[tuple[str, str], str] = {}
+
+
+def translate_with_ai_fallback(text: str, target_locale: str) -> str:
+    """Translate *text* using the configured AI provider as a fallback.
+
+    Returns the original *text* unchanged when:
+    * The target locale is English (source language)
+    * The AI provider is unavailable or returns an error
+    * The translation has already been cached
+
+    Results are cached in-memory for the lifetime of the process.
+    """
+    if target_locale == DEFAULT_LANGUAGE or target_locale not in SUPPORTED_LANGUAGE_CODES:
+        return text
+
+    cache_key = (text, target_locale)
+    if cache_key in _ai_translation_cache:
+        return _ai_translation_cache[cache_key]
+
+    target_name = next(
+        (lang["name"] for lang in SUPPORTED_LANGUAGES if lang["code"] == target_locale),
+        target_locale,
+    )
+
+    try:
+        from litellm import completion  # type: ignore[import-untyped]
+
+        from app.config import settings
+
+        model = getattr(settings, "ai_model", None) or getattr(settings, "openai_model", "gpt-4o-mini")
+        response = completion(
+            model=model,
+            messages=[
+                {
+                    "role": "system",
+                    "content": (
+                        f"You are a professional translator. Translate the following UI text "
+                        f"from English to {target_name}. Return ONLY the translated text, "
+                        f"nothing else. Keep any HTML tags, placeholders like {{name}}, "
+                        f"and special characters intact."
+                    ),
+                },
+                {"role": "user", "content": text},
+            ],
+            max_tokens=256,
+            temperature=0.1,
+        )
+        translated = response.choices[0].message.content.strip()
+        _ai_translation_cache[cache_key] = translated
+        return translated
+    except Exception:
+        logger.debug("AI fallback translation failed for '%s' → %s", text[:50], target_locale)
+        return text
+
+
+# ---------------------------------------------------------------------------
+# Language detection
+# ---------------------------------------------------------------------------
+
+
+def detect_language(request: Request) -> str:
+    """Determine the preferred UI language from the request context.
+
+    Resolution order:
+        1. ``preferred_language`` stored in the user session
+        2. ``docuelevate_lang`` cookie
+        3. ``Accept-Language`` HTTP header (best match)
+        4. Default → ``en``
+    """
+    # 1. User session preference
+    if hasattr(request, "session"):
+        session_lang = request.session.get("preferred_language")
+        if session_lang and session_lang in SUPPORTED_LANGUAGE_CODES:
+            return session_lang
+
+    # 2. Cookie
+    cookie_lang = request.cookies.get("docuelevate_lang")
+    if cookie_lang and cookie_lang in SUPPORTED_LANGUAGE_CODES:
+        return cookie_lang
+
+    # 3. Accept-Language header
+    accept = request.headers.get("accept-language", "")
+    lang = _parse_accept_language(accept)
+    if lang:
+        return lang
+
+    return DEFAULT_LANGUAGE
+
+
+def _parse_accept_language(header: str) -> str | None:
+    """Extract the best matching language from an ``Accept-Language`` header.
+
+    Parses quality values and returns the highest-priority match among
+    :data:`SUPPORTED_LANGUAGE_CODES`, or ``None`` if nothing matches.
+    """
+    if not header:
+        return None
+
+    entries: list[tuple[float, str]] = []
+    for raw_part in header.split(","):
+        part = raw_part.strip()
+        if not part:
+            continue
+        if ";q=" in part:
+            lang_tag, _, q_str = part.partition(";q=")
+            try:
+                quality = float(q_str.strip())
+            except ValueError:
+                quality = 0.0
+        else:
+            lang_tag = part
+            quality = 1.0
+        entries.append((quality, lang_tag.strip().lower()))
+
+    # Sort by quality descending
+    entries.sort(key=lambda e: e[0], reverse=True)
+
+    for _quality, tag in entries:
+        # Try exact match first (e.g., "de", "zh")
+        code = tag.split("-")[0]
+        if code in SUPPORTED_LANGUAGE_CODES:
+            return code
+
+    return None
+
+
+# ---------------------------------------------------------------------------
+# Localization helpers (l10n)
+# ---------------------------------------------------------------------------
+
+# Locale-specific formatting rules for date/number display
+_LOCALE_FORMATS: dict[str, dict[str, Any]] = {
+    "en": {
+        "date": "%B %d, %Y",
+        "date_short": "%m/%d/%Y",
+        "datetime": "%B %d, %Y %I:%M %p",
+        "thousands_sep": ",",
+        "decimal_sep": ".",
+    },
+    "de": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "fr": {
+        "date": "%d %B %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u202f",
+        "decimal_sep": ",",
+    },
+    "es": {
+        "date": "%d de %B de %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d de %B de %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "it": {
+        "date": "%d %B %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "pt": {
+        "date": "%d de %B de %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d de %B de %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "nl": {
+        "date": "%d %B %Y",
+        "date_short": "%d-%m-%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "nb": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "da": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "sv": {
+        "date": "%d %B %Y",
+        "date_short": "%Y-%m-%d",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "fi": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "is": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "ga": {
+        "date": "%d %B %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ",",
+        "decimal_sep": ".",
+    },
+    "lb": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "ca": {
+        "date": "%d de %B de %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d de %B de %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "pl": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "cs": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "sk": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "hu": {
+        "date": "%Y. %B %d.",
+        "date_short": "%Y.%m.%d.",
+        "datetime": "%Y. %B %d. %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "sl": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "hr": {
+        "date": "%d. %B %Y.",
+        "date_short": "%d.%m.%Y.",
+        "datetime": "%d. %B %Y. %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "ro": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "bg": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "el": {
+        "date": "%d %B %Y",
+        "date_short": "%d/%m/%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "et": {
+        "date": "%d. %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d. %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "lv": {
+        "date": "%Y. gada %d. %B",
+        "date_short": "%d.%m.%Y.",
+        "datetime": "%Y. gada %d. %B %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "lt": {
+        "date": "%Y m. %B %d d.",
+        "date_short": "%Y-%m-%d",
+        "datetime": "%Y m. %B %d d. %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "tr": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": ".",
+        "decimal_sep": ",",
+    },
+    "uk": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+    "zh": {
+        "date": "%Y年%m月%d日",
+        "date_short": "%Y/%m/%d",
+        "datetime": "%Y年%m月%d日 %H:%M",
+        "thousands_sep": ",",
+        "decimal_sep": ".",
+    },
+    "ru": {
+        "date": "%d %B %Y",
+        "date_short": "%d.%m.%Y",
+        "datetime": "%d %B %Y %H:%M",
+        "thousands_sep": "\u00a0",
+        "decimal_sep": ",",
+    },
+}
+
+
+def format_date(value: date | datetime | None, locale: str = DEFAULT_LANGUAGE, short: bool = False) -> str:
+    """Format a date/datetime value according to the locale conventions."""
+    if value is None:
+        return ""
+    fmt_key = "date_short" if short else "date"
+    fmt = _LOCALE_FORMATS.get(locale, _LOCALE_FORMATS[DEFAULT_LANGUAGE])[fmt_key]
+    return value.strftime(fmt)
+
+
+def format_datetime(value: datetime | None, locale: str = DEFAULT_LANGUAGE) -> str:
+    """Format a datetime value according to the locale conventions."""
+    if value is None:
+        return ""
+    fmt = _LOCALE_FORMATS.get(locale, _LOCALE_FORMATS[DEFAULT_LANGUAGE])["datetime"]
+    return value.strftime(fmt)
+
+
+def format_number(value: int | float, locale: str = DEFAULT_LANGUAGE) -> str:
+    """Format a number with locale-appropriate thousand separators."""
+    lf = _LOCALE_FORMATS.get(locale, _LOCALE_FORMATS[DEFAULT_LANGUAGE])
+    if isinstance(value, float):
+        int_part, _, dec_part = f"{value:,.2f}".partition(".")
+        formatted_int = int_part.replace(",", lf["thousands_sep"])
+        return f"{formatted_int}{lf['decimal_sep']}{dec_part}"
+    return f"{value:,}".replace(",", lf["thousands_sep"])
+
+
+@lru_cache(maxsize=32)
+def get_language_info(code: str) -> dict[str, str] | None:
+    """Return the metadata dict for a supported language code, or ``None``."""
+    for lang in SUPPORTED_LANGUAGES:
+        if lang["code"] == code:
+            return lang
+    return None

app/utils/settings_service.py

@@ -2065,6 +2065,78 @@ SETTING_METADATA = {
         "required": False,
         "restart_required": True,
     },
+    "audit_siem_enabled": {
+        "category": "Security",
+        "description": "Enable forwarding of audit events to an external SIEM system (Syslog, Splunk, Logstash, etc.).",
+        "type": "boolean",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_transport": {
+        "category": "Security",
+        "description": (
+            "Transport used to forward audit events. 'syslog' sends RFC 5424 messages over UDP/TCP. "
+            "'http' sends JSON POST payloads to a webhook URL (Splunk HEC, Logstash, Grafana Loki, etc.)."
+        ),
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+        "options": ["syslog", "http"],
+    },
+    "audit_siem_syslog_host": {
+        "category": "Security",
+        "description": "Hostname or IP of the syslog receiver.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_syslog_port": {
+        "category": "Security",
+        "description": "Port of the syslog receiver. Default: 514.",
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_syslog_protocol": {
+        "category": "Security",
+        "description": "Protocol for syslog transport: 'udp' or 'tcp'. Default: udp.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+        "options": ["udp", "tcp"],
+    },
+    "audit_siem_http_url": {
+        "category": "Security",
+        "description": (
+            "HTTP endpoint URL for SIEM webhook delivery. Supports Splunk HEC, "
+            "Logstash HTTP input, Grafana Loki push API, or any JSON-accepting endpoint."
+        ),
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_http_token": {
+        "category": "Security",
+        "description": "Bearer / HEC token included in the Authorization header of SIEM HTTP requests.",
+        "type": "string",
+        "sensitive": True,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_http_custom_headers": {
+        "category": "Security",
+        "description": "Comma-separated 'Key:Value' pairs of extra headers for SIEM HTTP requests.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
     # Rate Limiting
     "rate_limiting_enabled": {
         "category": "Security",

app/views/__init__.py

@@ -6,6 +6,7 @@ from fastapi import APIRouter
 
 from app.views.admin_users import router as admin_users_router
 from app.views.api_tokens import router as api_tokens_router
+from app.views.audit_logs import router as audit_logs_router
 from app.views.backup import router as backup_router
 from app.views.db_wizard import router as db_wizard_router
 from app.views.dropbox import router as dropbox_router
@@ -60,4 +61,5 @@ router.include_router(imap_accounts_router)  # Per-user IMAP ingestion accounts
 router.include_router(integrations_router)  # Unified integrations dashboard
 router.include_router(notifications_router)  # User notification dashboard
 router.include_router(scheduled_jobs_router)  # Admin scheduled batch jobs
+router.include_router(audit_logs_router)  # Comprehensive audit log viewer
 router.include_router(help_router)  # Built-in help / How-To docs

app/views/audit_logs.py

@@ -0,0 +1,46 @@
+"""
+Audit log viewer UI — admin-only page with filtering and SIEM status.
+"""
+
+import logging
+
+from fastapi import Depends, HTTPException, Request, status
+from sqlalchemy.orm import Session
+
+from app.views.base import APIRouter, get_db, require_login, settings, templates
+from app.views.settings import require_admin_access
+
+logger = logging.getLogger(__name__)
+router = APIRouter()
+
+
+@router.get("/admin/audit-logs")
+@require_login
+@require_admin_access
+async def audit_logs_page(request: Request, db: Session = Depends(get_db)):
+    """Comprehensive audit log viewer with filtering controls.
+
+    Displays a chronological log of all significant actions: logins,
+    document operations, settings changes, and admin actions.  The
+    actual data is fetched client-side via the ``/api/audit-logs`` JSON
+    endpoint so that filters, pagination, and live refresh work without
+    full-page reloads.
+    """
+    try:
+        siem_enabled = settings.audit_siem_enabled
+        siem_transport = settings.audit_siem_transport if siem_enabled else None
+        return templates.TemplateResponse(
+            "audit_logs.html",
+            {
+                "request": request,
+                "app_version": settings.version,
+                "siem_enabled": siem_enabled,
+                "siem_transport": siem_transport,
+            },
+        )
+    except Exception as e:
+        logger.error("Error loading audit logs page: %s", e)
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail="Failed to load audit logs page",
+        )

app/views/base.py

@@ -12,6 +12,14 @@ from sqlalchemy.orm import Session  # noqa: F401
 from app.auth import require_login  # noqa: F401
 from app.config import settings
 from app.database import get_db  # noqa: F401
+from app.utils.i18n import (
+    SUPPORTED_LANGUAGES,
+    detect_language,
+    format_date,
+    format_datetime,
+    format_number,
+    translate,
+)
 
 # Set up Jinja2 templates
 templates_dir = Path(__file__).parent.parent.parent / "frontend" / "templates"
@@ -21,6 +29,16 @@ templates = Jinja2Templates(directory=str(templates_dir))
 templates.env.globals["min"] = min
 templates.env.globals["max"] = max
 
+# ---------------------------------------------------------------------------
+# i18n Jinja2 integration
+# ---------------------------------------------------------------------------
+# The _() function is available in every template to translate UI strings.
+# Usage: {{ _("nav.dashboard") }} or {{ _("upload.max_size", size="10 MB") }}
+# The locale is automatically resolved from the request context.
+# ---------------------------------------------------------------------------
+
+templates.env.globals["supported_languages"] = SUPPORTED_LANGUAGES
+
 # Customize Jinja2Templates to include app_version in all templates
 original_template_response = templates.TemplateResponse
 
@@ -48,8 +66,31 @@ def _inject_global_context(ctx: dict) -> None:
             session_user = req.session.get("user")
         # When auth is disabled every visitor is effectively "logged in"
         ctx.setdefault("is_logged_in", not getattr(settings, "auth_enabled", True) or session_user is not None)
+
+        # --- i18n: detect language and register template helpers ---
+        current_locale = detect_language(req)
+        ctx.setdefault("current_locale", current_locale)
+
+        def _translate(key: str, **kwargs: object) -> str:
+            return translate(key, current_locale, **kwargs)
+
+        def _format_date(value: object, short: bool = False) -> str:
+            return format_date(value, current_locale, short=short)  # type: ignore[arg-type]
+
+        def _format_datetime(value: object) -> str:
+            return format_datetime(value, current_locale)  # type: ignore[arg-type]
+
+        def _format_number(value: object) -> str:
+            return format_number(value, current_locale)  # type: ignore[arg-type]
+
+        ctx.setdefault("_", _translate)
+        ctx.setdefault("format_date_l10n", _format_date)
+        ctx.setdefault("format_datetime_l10n", _format_datetime)
+        ctx.setdefault("format_number_l10n", _format_number)
     else:
         ctx.setdefault("is_logged_in", not getattr(settings, "auth_enabled", True))
+        ctx.setdefault("current_locale", "en")
+        ctx.setdefault("_", lambda key, **kw: translate(key, "en", **kw))
 
 
 def template_response_with_version(*args, **kwargs):

migrations/env.py

@@ -20,14 +20,30 @@ from app.database import Base
 
 # Ensure all models are imported so Base.metadata is populated.
 from app.models import (  # noqa: F401
+    ApiToken,
     ApplicationSettings,
+    AuditLog,
+    BackupRecord,
     DocumentMetadata,
     FileProcessingStep,
     FileRecord,
+    InAppNotification,
+    LocalUser,
     MobileDevice,
+    Pipeline,
+    PipelineStep,
     ProcessingLog,
     SavedSearch,
+    ScheduledJob,
     SettingsAuditLog,
+    SharedLink,
+    SubscriptionPlan,
+    UserImapAccount,
+    UserIntegration,
+    UserNotificationPreference,
+    UserNotificationTarget,
+    UserProfile,
+    WebhookConfig,
 )
 
 # Alembic Config object – provides access to values in alembic.ini.

migrations/versions/027_ensure_shared_links_table.py

@@ -0,0 +1,62 @@
+"""Ensure shared_links table exists for databases that skipped migration 025.
+
+Databases that were already at revision 025_add_user_notifications or
+026_add_scheduled_jobs before 025_add_shared_links was inserted into the
+migration chain will never have had the ``shared_links`` table created.
+This migration creates the table idempotently so those databases are
+repaired on the next ``alembic upgrade head``.
+
+Revision ID: 027_ensure_shared_links_table
+Revises: 026_add_scheduled_jobs
+Create Date: 2026-03-09
+"""
+
+from typing import Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "027_ensure_shared_links_table"
+down_revision: Union[str, None] = "026_add_scheduled_jobs"
+depends_on: Union[str, None] = None
+
+
+def upgrade() -> None:
+    """Create shared_links table if it does not already exist."""
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    if "shared_links" not in inspector.get_table_names():
+        op.create_table(
+            "shared_links",
+            sa.Column("id", sa.Integer(), nullable=False),
+            sa.Column("token", sa.String(64), nullable=False),
+            sa.Column("file_id", sa.Integer(), nullable=False),
+            sa.Column("owner_id", sa.String(), nullable=False),
+            sa.Column("label", sa.String(255), nullable=True),
+            sa.Column("expires_at", sa.DateTime(timezone=True), nullable=True),
+            sa.Column("max_views", sa.Integer(), nullable=True),
+            sa.Column("view_count", sa.Integer(), nullable=False, server_default="0"),
+            sa.Column("password_hash", sa.String(128), nullable=True),
+            sa.Column("is_active", sa.Boolean(), nullable=False, server_default="1"),
+            sa.Column("created_at", sa.DateTime(timezone=True), server_default=sa.func.now()),
+            sa.Column("revoked_at", sa.DateTime(timezone=True), nullable=True),
+            sa.ForeignKeyConstraint(["file_id"], ["files.id"]),
+            sa.PrimaryKeyConstraint("id"),
+            sa.UniqueConstraint("token"),
+        )
+        op.create_index("ix_shared_links_id", "shared_links", ["id"])
+        op.create_index("ix_shared_links_token", "shared_links", ["token"])
+        op.create_index("ix_shared_links_file_id", "shared_links", ["file_id"])
+        op.create_index("ix_shared_links_owner_id", "shared_links", ["owner_id"])
+
+
+def downgrade() -> None:
+    """Drop shared_links table only if this migration created it."""
+    conn = op.get_bind()
+    inspector = sa.inspect(conn)
+    if "shared_links" in inspector.get_table_names():
+        op.drop_index("ix_shared_links_owner_id", "shared_links")
+        op.drop_index("ix_shared_links_file_id", "shared_links")
+        op.drop_index("ix_shared_links_token", "shared_links")
+        op.drop_index("ix_shared_links_id", "shared_links")
+        op.drop_table("shared_links")

migrations/versions/028_add_audit_logs.py

@@ -0,0 +1,47 @@
+"""Add audit_logs table for comprehensive compliance audit logging.
+
+Revision ID: 028_add_audit_logs
+Revises: 027_ensure_shared_links_table
+Create Date: 2026-03-09
+"""
+
+from typing import Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "028_add_audit_logs"
+down_revision: Union[str, None] = "027_ensure_shared_links_table"
+depends_on: Union[str, None] = None
+
+
+def upgrade() -> None:
+    """Create audit_logs table."""
+    op.create_table(
+        "audit_logs",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("timestamp", sa.DateTime(timezone=True), server_default=sa.func.now(), nullable=False),
+        sa.Column("user", sa.String(), nullable=False),
+        sa.Column("action", sa.String(), nullable=False),
+        sa.Column("resource_type", sa.String(), nullable=True),
+        sa.Column("resource_id", sa.String(), nullable=True),
+        sa.Column("ip_address", sa.String(), nullable=True),
+        sa.Column("details", sa.Text(), nullable=True),
+        sa.Column("severity", sa.String(16), nullable=False, server_default="info"),
+        sa.PrimaryKeyConstraint("id"),
+    )
+    op.create_index("ix_audit_logs_id", "audit_logs", ["id"])
+    op.create_index("ix_audit_logs_timestamp", "audit_logs", ["timestamp"])
+    op.create_index("ix_audit_logs_user", "audit_logs", ["user"])
+    op.create_index("ix_audit_logs_action", "audit_logs", ["action"])
+    op.create_index("ix_audit_logs_resource_type", "audit_logs", ["resource_type"])
+
+
+def downgrade() -> None:
+    """Drop audit_logs table."""
+    op.drop_index("ix_audit_logs_resource_type", "audit_logs")
+    op.drop_index("ix_audit_logs_action", "audit_logs")
+    op.drop_index("ix_audit_logs_user", "audit_logs")
+    op.drop_index("ix_audit_logs_timestamp", "audit_logs")
+    op.drop_index("ix_audit_logs_id", "audit_logs")
+    op.drop_table("audit_logs")

migrations/versions/029_add_user_language_preference.py

@@ -0,0 +1,28 @@
+"""Add preferred_language column to user_profiles for i18n support.
+
+Revision ID: 029_add_user_language_preference
+Revises: 028_add_audit_logs
+Create Date: 2026-03-09
+"""
+
+from typing import Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "029_add_user_language_preference"
+down_revision: Union[str, None] = "028_add_audit_logs"
+depends_on: Union[str, None] = None
+
+
+def upgrade() -> None:
+    """Add preferred_language column to user_profiles table."""
+    op.add_column(
+        "user_profiles",
+        sa.Column("preferred_language", sa.String(10), nullable=True, server_default=None),
+    )
+
+
+def downgrade() -> None:
+    """Remove preferred_language column from user_profiles table."""
+    op.drop_column("user_profiles", "preferred_language")

migrations/versions/030_add_mobile_devices.py

@@ -1,7 +1,7 @@
 """Add mobile_devices table for push notification device registration.
 
-Revision ID: 027_add_mobile_devices
-Revises: 026_add_scheduled_jobs
+Revision ID: 030_add_mobile_devices
+Revises: 029_add_user_language_preference
 Create Date: 2026-03-10
 """
 
@@ -10,8 +10,8 @@ from typing import Union
 import sqlalchemy as sa
 from alembic import op
 
-revision: str = "027_add_mobile_devices"
-down_revision: Union[str, None] = "026_add_scheduled_jobs"
+revision: str = "030_add_mobile_devices"
+down_revision: Union[str, None] = "029_add_user_language_preference"
 depends_on: Union[str, None] = None