refactor: Clean up layout store and implement proper CRDT operations

- Created dedicated layoutOperations.ts with production-grade CRDT interfaces
- Integrated existing QuadTree spatial index instead of simple cache
- Split composables into separate files (useLayout, useNodeLayout, useLayoutSync)
- Cleaned up operation handlers using specific types instead of Extract
- Added proper operation interfaces with type guards and extensibility
- Updated all type references to use new operation structure

The layout store now properly uses the existing QuadTree infrastructure for
efficient spatial queries and follows CRDT best practices with well-defined
operation interfaces.

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

Co-Authored-By: Claude <noreply@anthropic.com>

tests-ui/tests/stores/layoutStore.test.ts

@@ -154,13 +154,13 @@ describe('layoutStore CRDT operations', () => {
     })
 
     // Wait for async notification
-    await new Promise(resolve => setTimeout(resolve, 50))
-    
+    await new Promise((resolve) => setTimeout(resolve, 50))
+
     expect(changes.length).toBeGreaterThanOrEqual(1)
     const lastChange = changes[changes.length - 1]
     expect(lastChange.source).toBe('vue')
     expect(lastChange.operation.actor).toBe('user-123')
-    
+
     unsubscribe()
   })
 
@@ -229,6 +229,7 @@ describe('layoutStore CRDT operations', () => {
       type: 'moveNode',
       nodeId,
       position: { x: 150, y: 150 },
+      previousPosition: { x: 100, y: 100 },
       timestamp: startTime + 100,
       source: 'vue',
       actor: 'test-actor'
@@ -245,4 +246,4 @@ describe('layoutStore CRDT operations', () => {
     expect(recentOps.length).toBeGreaterThanOrEqual(1)
     expect(recentOps[0].type).toBe('moveNode')
   })
-})
+})