feat: add Apprise alerting capabilities with user and admin notification channels

Agent-Logs-Url: https://github.com/christianlouis/pop_puller_to_gmail/sessions/858e72a6-5282-4ce8-b38a-db4b9e2e6f65

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

backend/app/models/schemas.py

@@ -225,7 +225,10 @@ class NotificationConfigBase(BaseModel):
     channel: NotificationChannel
     apprise_url: Optional[str] = Field(None, description="Apprise notification URL")
     is_enabled: bool = True
-    config: Dict[str, Any] = Field(default_factory=dict)
+    config: Dict[str, Any] = Field(
+        default_factory=dict,
+        description="Legacy channel-specific configuration (deprecated in favour of apprise_url)",
+    )
     notify_on_errors: bool = True
     notify_on_success: bool = False
     notify_threshold: int = Field(default=3, gt=0, le=100)

backend/app/services/notification_service.py

@@ -60,7 +60,7 @@ async def send_user_notification(
             continue
 
         try:
-            success = await _send_apprise(str(config.apprise_url), title, body)
+            success = await _send_apprise(config.apprise_url or "", title, body)
             if success:
                 sent += 1
         except Exception as exc:
@@ -99,7 +99,7 @@ async def send_admin_notification(
     sent = 0
     for config in configs:
         try:
-            success = await _send_apprise(str(config.apprise_url), title, body)
+            success = await _send_apprise(config.apprise_url or "", title, body)
             if success:
                 sent += 1
         except Exception as exc: