feat(chunking): add AST-aware code chunking for Go, Python, TypeScript

- [x] Add language-specific chunkers with AST parsing (Go, Python, TypeScript)
- [x] Implement chunking manager to dispatch files to appropriate chunkers
- [x] Integrate code chunks into vector sync for semantic search
- [x] Add tree-sitter dependency for Python/TypeScript parsing
- [x] Reorder struct fields for consistency across codebase
- [x] Rename error variables to follow Go conventions (err → unmarshalErr, etc.)
- [x] Add code chunk metadata to vector documents (language, symbol name, line ranges)
- [x] Update worker service to initialize chunking pipeline with all three languages

internal/watcher/watcher.go

@@ -16,15 +16,15 @@ import (
 // Watcher monitors a file or directory for deletion and calls onDelete when removed.
 // It watches the parent directory since fsnotify cannot watch non-existent files.
 type Watcher struct {
-	targetPath string // The file/directory to watch for deletion
-	parentPath string // Parent directory (what we actually watch)
-	onDelete   func() // Callback when target is deleted
-	watcher    *fsnotify.Watcher
 	ctx        context.Context
+	onDelete   func()
+	watcher    *fsnotify.Watcher
 	cancel     context.CancelFunc
+	targetPath string
+	parentPath string
+	debounce   time.Duration
 	mu         sync.Mutex
 	running    bool
-	debounce   time.Duration
 }
 
 // New creates a new Watcher for the given target path.