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/mcp/server.go

@@ -15,10 +15,10 @@ import (
 
 // Server is the MCP server that exposes search tools.
 type Server struct {
-	searchMgr *search.Manager
-	version   string
 	stdin     io.Reader
 	stdout    io.Writer
+	searchMgr *search.Manager
+	version   string
 }
 
 // NewServer creates a new MCP server.
@@ -41,17 +41,17 @@ type Request struct {
 
 // Response represents a JSON-RPC response.
 type Response struct {
-	JSONRPC string `json:"jsonrpc"`
 	ID      any    `json:"id"`
 	Result  any    `json:"result,omitempty"`
 	Error   *Error `json:"error,omitempty"`
+	JSONRPC string `json:"jsonrpc"`
 }
 
 // Error represents a JSON-RPC error.
 type Error struct {
-	Code    int    `json:"code"`
-	Message string `json:"message"`
 	Data    any    `json:"data,omitempty"`
+	Message string `json:"message"`
+	Code    int    `json:"code"`
 }
 
 // ToolCallParams represents parameters for tools/call method.
@@ -62,9 +62,9 @@ type ToolCallParams struct {
 
 // Tool represents an MCP tool definition.
 type Tool struct {
+	InputSchema map[string]any `json:"inputSchema"`
 	Name        string         `json:"name"`
 	Description string         `json:"description"`
-	InputSchema map[string]any `json:"inputSchema"`
 }
 
 // Run starts the MCP server loop.
@@ -440,17 +440,17 @@ func (s *Server) callTool(ctx context.Context, name string, args json.RawMessage
 
 // TimelineParams represents parameters for timeline operations.
 type TimelineParams struct {
-	AnchorID  int64  `json:"anchor_id"`
 	Query     string `json:"query"`
-	Before    int    `json:"before"`
-	After     int    `json:"after"`
 	Project   string `json:"project"`
 	ObsType   string `json:"obs_type"`
 	Concepts  string `json:"concepts"`
 	Files     string `json:"files"`
+	Format    string `json:"format"`
+	AnchorID  int64  `json:"anchor_id"`
+	Before    int    `json:"before"`
+	After     int    `json:"after"`
 	DateStart int64  `json:"dateStart"`
 	DateEnd   int64  `json:"dateEnd"`
-	Format    string `json:"format"`
 }
 
 // handleTimeline handles timeline requests.

internal/mcp/server_test.go

@@ -34,8 +34,8 @@ func (s *ServerSuite) TestNewServer() {
 func TestRequest(t *testing.T) {
 	tests := []struct {
 		name     string
-		req      Request
 		expected string
+		req      Request
 	}{
 		{
 			name: "initialize request",
@@ -137,10 +137,10 @@ func TestResponse(t *testing.T) {
 
 // TestError tests Error struct.
 func TestError(t *testing.T) {
-	tests := []struct {
-		name     string
+	tests := []struct { //nolint:govet
 		err      Error
 		expected string
+		name     string
 	}{
 		{
 			name: "parse error",
@@ -365,11 +365,11 @@ func TestHandleRequest(t *testing.T) {
 	ctx := context.Background()
 
 	tests := []struct {
-		name         string
 		req          *Request
-		expectError  bool
-		errorCode    int
+		name         string
 		errorMessage string
+		errorCode    int
+		expectError  bool
 	}{
 		{
 			name: "initialize method",
@@ -683,10 +683,8 @@ func TestRun_MultipleRequests(t *testing.T) {
 func TestHandleTimeline_Defaults(t *testing.T) {
 	// Test that handleTimeline sets default before/after values
 	params := TimelineParams{
-		AnchorID: 0,
-		Query:    "",
-		Before:   0,
-		After:    0,
+		Before: 0,
+		After:  0,
 	}
 
 	// Simulate the default value assignment from handleTimeline
@@ -753,13 +751,13 @@ func TestServerStdinStdoutConfig(t *testing.T) {
 // TestResponseIDTypes tests that response IDs can be various types.
 func TestResponseIDTypes(t *testing.T) {
 	tests := []struct {
-		name string
 		id   any
+		name string
 	}{
-		{"integer id", 1},
-		{"string id", "abc-123"},
-		{"float id", 1.5},
-		{"null id", nil},
+		{name: "integer id", id: 1},
+		{name: "string id", id: "abc-123"},
+		{name: "float id", id: 1.5},
+		{name: "null id", id: nil},
 	}
 
 	for _, tt := range tests {