fix: all lint errors, test + lint pre-commit passing

Frontend:
- Split nodeTypes/edgeTypes into separate .ts files (react-refresh)
- Remove setState-in-effect in NodeModal (key prop reset)
- Fix handleSave accessed before declaration (useRef pattern)
- Exclude src/components/ui/** from eslint (shadcn generated)
- Use defineConfig from vitest/config for test type support

Backend:
- ruff --fix: sort imports, datetime.UTC alias
- Raise line-length to 120, ignore E501 in tests
- Break long update_node/update_edge signatures
- pyproject.toml: per-file-ignores for tests

backend/app/api/routes/nodes.py

@@ -34,7 +34,9 @@ async def get_node(node_id: str, db: AsyncSession = Depends(get_db), _: str = De
 
 
 @router.patch("/{node_id}", response_model=NodeResponse)
-async def update_node(node_id: str, body: NodeUpdate, db: AsyncSession = Depends(get_db), _: str = Depends(get_current_user)):
+async def update_node(
+    node_id: str, body: NodeUpdate, db: AsyncSession = Depends(get_db), _: str = Depends(get_current_user)
+):
     node = await db.get(Node, node_id)
     if not node:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Node not found")