ci: fix remaining lint/type errors - react-compiler deps, None-indexable

backend/app/db/database.py

@@ -186,7 +186,8 @@ async def init_db() -> None:
         # Seed default Network Topology design if designs table is empty
         _default_design_id = str(_uuid_mod.uuid4())
         row = await conn.exec_driver_sql("SELECT COUNT(*) FROM designs")
-        count = (row.fetchone())[0]
+        count_row = row.fetchone()
+        count = count_row[0] if count_row else 0
         if count == 0:
             await conn.exec_driver_sql(
                 "INSERT INTO designs (id, name, design_type, created_at, updated_at) "

frontend/src/App.tsx

@@ -118,7 +118,7 @@ export default function App() {
     } catch {
       loadCanvas(demoNodes, demoEdges)
     }
-  }, [loadCanvas, setTheme, setCustomStyle, demoNodes, demoEdges])
+  }, [loadCanvas, setTheme, setCustomStyle])
 
   const loadDesignsAndCanvas = useCallback(async () => {
     if (STANDALONE) return
@@ -135,7 +135,7 @@ export default function App() {
       // If API fails (e.g. fresh DB with no designs), fall back to demo data
       loadCanvas(demoNodes, demoEdges)
     }
-  }, [setDesigns, setActiveDesign, loadCanvasFromApi, activeDesignId, demoNodes, demoEdges])
+  }, [setDesigns, setActiveDesign, loadCanvasFromApi, activeDesignId, loadCanvas])
 
   // Load canvas on auth (or immediately in standalone mode)
   useEffect(() => {