feat(05-01): create AST-aligned chunking engine with symbol tree builder

- Add src/utils/ast-chunker.ts with buildSymbolTree, generateASTChunks,
  mergeSmallSymbolChunks, splitOversizedChunks, createASTAlignedChunks
- Add typed symbol metadata fields to ChunkMetadata in types/index.ts
  (symbolAware, symbolName, symbolKind, symbolPath, parentSymbol, chunkStrategy)
- Leaf symbols become single chunks, containers split at method boundaries
- Gap/filler chunks cover regions between symbols for full file coverage
- Safe split points at blank lines, comments, closing braces

Author: PatrickSys

src/types/index.ts

@@ -144,6 +144,14 @@ export interface ChunkMetadata {
   className?: string;
   functionName?: string;
 
+  // Symbol-aware chunking (AST-aligned)
+  symbolAware?: boolean;
+  symbolName?: string;
+  symbolKind?: string;
+  symbolPath?: string[];
+  parentSymbol?: string;
+  chunkStrategy?: string;
+
   // Framework-specific
   isStandalone?: boolean;
   selector?: string;