fix: restore all code deleted/truncated by d2217531 Jules SSRF commit

Commit d2217531 (google-labs-jules SSRF fix) catastrophically deleted
11,500+ lines across 100+ files while fixing an unrelated IMAP issue.

Restored from d2217531^ (pre-bad-commit state):

Deleted files (fully restored):
- app/api/{automation,classification_rules,comments,sharing}.py
- app/middleware/upload_rate_limit.py
- app/tasks/{automation_tasks,classify_document}.py
- app/utils/{automation_hooks,classification_rules}.py
- docs/AppleAppStoreCompliance.md
- frontend/input.css, package.json, package-lock.json, tailwind.config.js
- frontend/static/js/{annotations,claim,comments,sharing}.js
- frontend/templates/{admin_connections,file_annotations,file_summary}.html
- tests/{test_api_files_comprehensive,test_auth_extended,test_sharing,
         test_comments,test_connections,test_imap_profiles,test_api_sessions,
         test_automation,test_classification_rules,test_api_advanced_filters,
         test_api_classification_rules,test_upload_rate_limit,test_api_dropbox,
         test_classify_document,test_comments_ui,test_upload_to_icloud,
         test_api_onedrive_comprehensive,test_frontend_build,test_sentry,
         test_diagnostic,test_database,test_views_dropbox,test_local_auth}.py

Truncated files (content restored):
- app/{auth,config,main,models,celery_worker,database}.py
- app/api/{__init__,api_tokens,diagnostic,dropbox,files,google_drive,
           integrations,local_auth,mobile,onedrive,pipelines,qr_auth,
           settings,url_upload}.py
- app/middleware/upload_rate_limit.py
- app/tasks/upload_to_nextcloud.py
- app/utils/{allowed_types,settings_service,settings_sync,user_scope,webhook}.py
- app/views/{base,dropbox,files,google_drive,onedrive,settings}.py
- docs/{API,AuthenticationSetup,ConfigurationGuide,DatabaseConfiguration,
        DeploymentGuide,DropboxSetup,GoogleDriveSetup,KubernetesDeployment,
        MobileApp,OneDriveSetup,ProductionReadiness,SentrySetup,
        SocialLoginSetup,UserGuide}.md
- frontend/static/{js/upload.js,styles.css}
- frontend/templates/{api_tokens,base,devices,dropbox,dropbox_callback,
                      file_view,files,google_drive,onedrive,onedrive_callback,
                      signup}.html
- frontend/translations/en.json
- migrations/env.py
- tests/{conftest,test_api_integrations,test_api_mobile,test_api_settings,
         test_api_tokens,test_audit_logs,test_duplicates,test_imap_tasks,
         test_setup_wizard,test_views_files_comprehensive}.py

Security fixes kept from post-d2217531 commits:
- app/utils/network.py: DNS SSRF fail-secure fix (06b0fced)
- app/utils/file_operations.py: path traversal fix (1018ea17)
- tests/test_imap_tasks.py: re-applied 4 is_private_ip mock patches

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>
Agent-Logs-Url: https://github.com/christianlouis/DocuElevate/sessions/51133dd8-9bec-41ab-aa10-3de753634187

app/database.py

@@ -18,22 +18,37 @@ logger = logging.getLogger(__name__)
 
 Base = declarative_base()
 
-# Parse the DATABASE_URL
+# ---------------------------------------------------------------------------
+# Engine construction
+# ---------------------------------------------------------------------------
 DB_URL = settings.database_url
-_db_url = make_url(DB_URL)
-if _db_url.get_backend_name() == "sqlite":
-    # SQLite does not benefit from connection pooling; NullPool avoids contention.
-    engine = create_engine(DB_URL, connect_args={"check_same_thread": False}, poolclass=NullPool)
+_parsed_url = make_url(DB_URL)
+
+_connect_args: dict[str, Any] = {}
+_engine_kwargs: dict[str, Any] = {
+    "pool_pre_ping": True,  # detect stale / dropped connections before use
+}
+
+if _parsed_url.get_backend_name() == "sqlite":
+    # SQLite does not benefit from connection pooling and is prone to
+    # QueuePool exhaustion under concurrent access.  NullPool opens a fresh
+    # connection for each request and closes it immediately afterwards,
+    # completely avoiding the "QueuePool limit reached" TimeoutError.
+    _connect_args["check_same_thread"] = False
+    _engine_kwargs["poolclass"] = NullPool
 else:
-    # PostgreSQL / MySQL / other: use a configurable QueuePool.
-    engine = create_engine(
-        DB_URL,
-        poolclass=QueuePool,
-        pool_size=settings.db_pool_size,
-        max_overflow=settings.db_max_overflow,
-        pool_timeout=settings.db_pool_timeout,
-        pool_recycle=settings.db_pool_recycle,
+    # PostgreSQL / MySQL — use a bounded QueuePool with configurable limits.
+    _engine_kwargs["poolclass"] = QueuePool
+    _engine_kwargs.update(
+        {
+            "pool_size": settings.db_pool_size,
+            "max_overflow": settings.db_max_overflow,
+            "pool_timeout": settings.db_pool_timeout,
+            "pool_recycle": settings.db_pool_recycle,
+        }
     )
+
+engine = create_engine(DB_URL, connect_args=_connect_args, **_engine_kwargs)
 SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)