- Convert class-based LayoutMutations to useLayoutMutations() composable (#5346)

- Remove unnecessary useLayout wrapper that added boilerplate
- Use LayoutMutations interface directly in LGraph instead of redefining types
- Update all components to use composable pattern consistently

tests-ui/tests/litegraph/core/__snapshots__/LGraph.test.ts.snap

@@ -281,6 +281,21 @@ LGraph {
   "id": "b4e984f1-b421-4d24-b8b4-ff895793af13",
   "iteration": 0,
   "last_update_time": 0,
+  "layoutMutations": {
+    "bringNodeToFront": [Function],
+    "createLink": [Function],
+    "createNode": [Function],
+    "createReroute": [Function],
+    "deleteLink": [Function],
+    "deleteNode": [Function],
+    "deleteReroute": [Function],
+    "moveNode": [Function],
+    "moveReroute": [Function],
+    "resizeNode": [Function],
+    "setActor": [Function],
+    "setNodeZIndex": [Function],
+    "setSource": [Function],
+  },
   "links": Map {},
   "list_of_graphcanvas": null,
   "nodes_actioning": [],