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

cmd/hooks/user-prompt/main.go

@@ -35,8 +35,8 @@ func main() {
 	}
 
 	var input Input
-	if err := json.Unmarshal(inputData, &input); err != nil {
-		hooks.WriteError("UserPromptSubmit", err)
+	if unmarshalErr := json.Unmarshal(inputData, &input); unmarshalErr != nil {
+		hooks.WriteError("UserPromptSubmit", unmarshalErr)
 		os.Exit(1)
 	}