[refactor] Improve renderer domain organization (#5552)

* [refactor] Improve renderer architecture organization

Building on PR #5388, this refines the renderer domain structure:

**Key improvements:**
- Group all transform utilities in `transform/` subdirectory for better cohesion
- Move canvas state to dedicated `renderer/core/canvas/` domain
- Consolidate coordinate system logic (TransformPane, useTransformState, sync utilities)

**File organization:**
- `renderer/core/canvas/canvasStore.ts` (was `stores/graphStore.ts`)
- `renderer/core/layout/transform/` contains all coordinate system utilities
- Transform sync utilities co-located with core transform logic

This creates clearer domain boundaries and groups related functionality
while building on the foundation established in PR #5388.

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

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

* fix: Clean up linter-modified files

* Fix import paths and clean up unused imports after rebase

- Update all remaining @/stores/graphStore references to @/renderer/core/canvas/canvasStore
- Remove unused imports from selection toolbox components
- All tests pass, only reka-ui upstream issue remains in typecheck

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

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

* [auto-fix] Apply ESLint and Prettier fixes

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>

tests-ui/tests/composables/graph/useCanvasInteractions.test.ts

@@ -2,13 +2,19 @@ import { beforeEach, describe, expect, it, vi } from 'vitest'
 
 import { useCanvasInteractions } from '@/composables/graph/useCanvasInteractions'
 import type { LGraphCanvas } from '@/lib/litegraph/src/litegraph'
-import { useCanvasStore } from '@/stores/graphStore'
+import { useCanvasStore } from '@/renderer/core/canvas/canvasStore'
 import { useSettingStore } from '@/stores/settingStore'
 
 // Mock stores
-vi.mock('@/stores/graphStore', () => {
+vi.mock('@/renderer/core/canvas/canvasStore', () => {
   const getCanvas = vi.fn()
-  return { useCanvasStore: vi.fn(() => ({ getCanvas })) }
+  const setCursorStyle = vi.fn()
+  return {
+    useCanvasStore: vi.fn(() => ({
+      getCanvas,
+      setCursorStyle
+    }))
+  }
 })
 vi.mock('@/stores/settingStore', () => {
   const getFn = vi.fn()