Add server dbpurgeage warning state in API and mark task complete

backend/app/models/server.py

@@ -56,3 +56,7 @@ class ServerSettingsResponse(BaseModel):
     model_config = ConfigDict(strict=True)
 
     settings: ServerSettings
+    warnings: dict[str, bool] = Field(
+        default_factory=dict,
+        description="Warnings highlighting potentially unsafe settings.",
+    )

backend/app/services/server_service.py

@@ -160,8 +160,12 @@ async def get_settings(socket_path: str) -> ServerSettingsResponse:
         db_max_matches=db_max_matches,
     )
 
-    log.info("server_settings_fetched")
-    return ServerSettingsResponse(settings=settings)
+    warnings: dict[str, bool] = {
+        "db_purge_age_too_low": db_purge_age < 86400,
+    }
+
+    log.info("server_settings_fetched", db_purge_age=db_purge_age, warnings=warnings)
+    return ServerSettingsResponse(settings=settings, warnings=warnings)
 
 
 async def update_settings(socket_path: str, update: ServerSettingsUpdate) -> None:

backend/tests/test_routers/test_server.py

@@ -68,7 +68,8 @@ def _make_settings() -> ServerSettingsResponse:
             db_path="/var/lib/fail2ban/fail2ban.sqlite3",
             db_purge_age=86400,
             db_max_matches=10,
-        )
+        ),
+        warnings={"db_purge_age_too_low": False},
     )
 
 
@@ -93,6 +94,7 @@ class TestGetServerSettings:
         data = resp.json()
         assert data["settings"]["log_level"] == "INFO"
         assert data["settings"]["db_purge_age"] == 86400
+        assert data["warnings"]["db_purge_age_too_low"] is False
 
     async def test_401_when_unauthenticated(self, server_client: AsyncClient) -> None:
         """GET /api/server/settings returns 401 without session."""

backend/tests/test_services/test_server_service.py

@@ -63,6 +63,16 @@ class TestGetSettings:
         assert result.settings.log_target == "/var/log/fail2ban.log"
         assert result.settings.db_purge_age == 86400
         assert result.settings.db_max_matches == 10
+        assert result.warnings == {"db_purge_age_too_low": False}
+
+    async def test_db_purge_age_warning_when_below_minimum(self) -> None:
+        """get_settings sets warning when db_purge_age is below 86400 seconds."""
+        responses = {**_DEFAULT_RESPONSES, "get|dbpurgeage": (0, 3600)}
+        with _patch_client(responses):
+            result = await server_service.get_settings(_SOCKET)
+
+        assert result.settings.db_purge_age == 3600
+        assert result.warnings == {"db_purge_age_too_low": True}
 
     async def test_db_path_parsed(self) -> None:
         """get_settings returns the correct database file path."""