feat: persist system settings and refine admin layouts

backend/app/db/session.py

@@ -25,11 +25,52 @@ async def get_db() -> AsyncGenerator[AsyncSession, None]:
             raise
 
 
+async def seed_default_datasources(session: AsyncSession):
+    from app.core.datasource_defaults import DEFAULT_DATASOURCES
+    from app.models.datasource import DataSource
+
+    for source, info in DEFAULT_DATASOURCES.items():
+        existing = await session.get(DataSource, info["id"])
+        if existing:
+            existing.name = info["name"]
+            existing.source = source
+            existing.module = info["module"]
+            existing.priority = info["priority"]
+            existing.frequency_minutes = info["frequency_minutes"]
+            existing.collector_class = source
+            if existing.config is None:
+                existing.config = "{}"
+            continue
+
+        session.add(
+            DataSource(
+                id=info["id"],
+                name=info["name"],
+                source=source,
+                module=info["module"],
+                priority=info["priority"],
+                frequency_minutes=info["frequency_minutes"],
+                collector_class=source,
+                config="{}",
+                is_active=True,
+            )
+        )
+
+    await session.commit()
+
+
 async def init_db():
     import app.models.user  # noqa: F401
     import app.models.gpu_cluster  # noqa: F401
     import app.models.task  # noqa: F401
     import app.models.datasource  # noqa: F401
+    import app.models.datasource_config  # noqa: F401
+    import app.models.alert  # noqa: F401
+    import app.models.collected_data  # noqa: F401
+    import app.models.system_setting  # noqa: F401
 
     async with engine.begin() as conn:
         await conn.run_sync(Base.metadata.create_all)
+
+    async with async_session_factory() as session:
+        await seed_default_datasources(session)