Add Apprise alerting capabilities (backend)

- Add name + apprise_url columns to NotificationConfig model
- Add AdminNotificationConfig model for system-wide alert channels
- Create NotificationService with send_user_notification,
  send_admin_notification, and test_notification helpers
- Replace stub notifications.py with full CRUD + /test endpoint
- Add admin notification config CRUD + /test to admin.py
- Update NotificationConfig schemas: name required, apprise_url
  optional, config optional (default {})
- Add AdminNotificationConfig* schemas
- Integrate send_user_notification into process_mail_account task
  for Gmail revocation, forwarding failures, and exceptions
- Update CHANGELOG.md

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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

backend/app/api/v1/endpoints/notifications.py

@@ -1,7 +1,7 @@
 """Notification configuration endpoints"""
 
 from typing import List
-from fastapi import APIRouter, Depends, status
+from fastapi import APIRouter, Depends, HTTPException, status
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy import select
 
@@ -10,8 +10,12 @@ from app.core.deps import get_current_active_user
 from app.models.database_models import User, NotificationConfig
 from app.models.schemas import (
     NotificationConfigCreate,
+    NotificationConfigUpdate,
     NotificationConfigResponse,
+    NotificationTestRequest,
+    NotificationTestResponse,
 )
+from app.services.notification_service import test_notification
 
 router = APIRouter()
 
@@ -24,7 +28,7 @@ async def create_notification_config(
     current_user: User = Depends(get_current_active_user),
     db: AsyncSession = Depends(get_db),
 ):
-    """Create notification configuration"""
+    """Create a new notification configuration"""
     config = NotificationConfig(user_id=current_user.id, **config_in.dict())
     db.add(config)
     await db.commit()
@@ -37,8 +41,94 @@ async def list_notification_configs(
     current_user: User = Depends(get_current_active_user),
     db: AsyncSession = Depends(get_db),
 ):
-    """List all notification configurations"""
+    """List all notification configurations for the current user"""
     result = await db.execute(
         select(NotificationConfig).where(NotificationConfig.user_id == current_user.id)
     )
     return result.scalars().all()
+
+
+@router.get("/{config_id}", response_model=NotificationConfigResponse)
+async def get_notification_config(
+    config_id: int,
+    current_user: User = Depends(get_current_active_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Get a specific notification configuration"""
+    result = await db.execute(
+        select(NotificationConfig).where(
+            NotificationConfig.id == config_id,
+            NotificationConfig.user_id == current_user.id,
+        )
+    )
+    config = result.scalar_one_or_none()
+    if not config:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Notification config not found",
+        )
+    return config
+
+
+@router.put("/{config_id}", response_model=NotificationConfigResponse)
+async def update_notification_config(
+    config_id: int,
+    config_in: NotificationConfigUpdate,
+    current_user: User = Depends(get_current_active_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Update a notification configuration"""
+    result = await db.execute(
+        select(NotificationConfig).where(
+            NotificationConfig.id == config_id,
+            NotificationConfig.user_id == current_user.id,
+        )
+    )
+    config = result.scalar_one_or_none()
+    if not config:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Notification config not found",
+        )
+
+    update_data = config_in.dict(exclude_unset=True)
+    for field, value in update_data.items():
+        setattr(config, field, value)
+
+    await db.commit()
+    await db.refresh(config)
+    return config
+
+
+@router.delete("/{config_id}", status_code=status.HTTP_204_NO_CONTENT)
+async def delete_notification_config(
+    config_id: int,
+    current_user: User = Depends(get_current_active_user),
+    db: AsyncSession = Depends(get_db),
+):
+    """Delete a notification configuration"""
+    result = await db.execute(
+        select(NotificationConfig).where(
+            NotificationConfig.id == config_id,
+            NotificationConfig.user_id == current_user.id,
+        )
+    )
+    config = result.scalar_one_or_none()
+    if not config:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail="Notification config not found",
+        )
+
+    await db.delete(config)
+    await db.commit()
+
+
+@router.post("/test", response_model=NotificationTestResponse)
+async def test_notification_config(
+    request: NotificationTestRequest,
+    current_user: User = Depends(get_current_active_user),
+):
+    """Test a notification channel by sending a test message"""
+    success, message = await test_notification(request.apprise_url)
+    return NotificationTestResponse(success=success, message=message)