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/renderer/core/layout/constants.ts

@@ -0,0 +1,73 @@
+/**
+ * Layout System Constants
+ *
+ * Centralized configuration values for the layout system.
+ * These values control spatial indexing, performance, and behavior.
+ */
+
+/**
+ * QuadTree configuration for spatial indexing
+ */
+export const QUADTREE_CONFIG = {
+  /** Default bounds for the QuadTree - covers a large canvas area */
+  DEFAULT_BOUNDS: {
+    x: -10000,
+    y: -10000,
+    width: 20000,
+    height: 20000
+  },
+  /** Maximum tree depth to prevent excessive subdivision */
+  MAX_DEPTH: 6,
+  /** Maximum items per node before subdivision */
+  MAX_ITEMS_PER_NODE: 4
+} as const
+
+/**
+ * Performance and optimization settings
+ */
+export const PERFORMANCE_CONFIG = {
+  /** RAF-based change detection interval (roughly 60fps) */
+  CHANGE_DETECTION_INTERVAL: 16,
+  /** Spatial query cache TTL in milliseconds */
+  SPATIAL_CACHE_TTL: 1000,
+  /** Maximum cache size for spatial queries */
+  SPATIAL_CACHE_MAX_SIZE: 100,
+  /** Batch update delay in milliseconds */
+  BATCH_UPDATE_DELAY: 4
+} as const
+
+/**
+ * Default values for node layout
+ */
+export const NODE_DEFAULTS = {
+  /** Default node size when not specified */
+  SIZE: { width: 200, height: 100 },
+  /** Default z-index for new nodes */
+  Z_INDEX: 0,
+  /** Default visibility state */
+  VISIBLE: true
+} as const
+
+/**
+ * Debug and development settings
+ */
+export const DEBUG_CONFIG = {
+  /** LocalStorage key for enabling layout debug mode */
+  LAYOUT_DEBUG_KEY: 'layout-debug',
+  /** Logger name for layout system */
+  LOGGER_NAME: 'layout',
+  /** Logger name for layout store */
+  STORE_LOGGER_NAME: 'layout-store'
+} as const
+
+/**
+ * Actor and source identifiers
+ */
+export const ACTOR_CONFIG = {
+  /** Prefix for auto-generated actor IDs */
+  USER_PREFIX: 'user-',
+  /** Length of random suffix for actor IDs */
+  ID_LENGTH: 9,
+  /** Default source when not specified */
+  DEFAULT_SOURCE: 'external' as const
+} as const