refactor: Reorganize layout system into new renderer architecture (#5071)

- Move layout system to renderer/core/layout/
  - Store, operations, adapters, and sync modules organized clearly
  - Merged layoutTypes.ts and layoutOperations.ts into single types.ts
- Move canvas rendering to renderer/core/canvas/
  - LiteGraph-specific code in litegraph/ subdirectory
  - PathRenderer at canvas level
- Move spatial indexing to renderer/core/spatial/
- Move Vue node composables to renderer/extensions/vue-nodes/
- Update all import paths throughout codebase
- Apply consistent naming (renderer vs rendering)

This establishes clearer separation between core rendering concerns
and optional extensions, making the architecture more maintainable.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-authored-by: Claude <noreply@anthropic.com>

src/composables/graph/useNodeChangeDetection.ts

@@ -7,7 +7,7 @@
 import { reactive } from 'vue'
 
 import type { LGraph, LGraphNode } from '@/lib/litegraph/src/litegraph'
-import { layoutMutations } from '@/services/layoutMutations'
+import { layoutMutations } from '@/renderer/core/layout/operations/LayoutMutations'
 
 export interface ChangeDetectionMetrics {
   updateTime: number