feat(leann-phase2): implement hybrid vector storage and graph-based search

- [x] Add AST-aware code chunking for Go, Python, and TypeScript using tree-sitter
- [x] Implement LEANN-inspired hybrid vector storage with hub detection and selective embedding storage (60-80% savings)
- [x] Add observation relationship graph with CSR format and edge detection (file overlap, semantic similarity, temporal, concept)
- [x] Implement graph-aware search with two-level traversal and relationship-based ranking
- [x] Add auto-tuning system for dynamic hub threshold adjustment based on query performance
- [x] Add comprehensive metrics tracking for vector storage, queries, latency, and graph traversals
- [x] Update configuration system with graph and hybrid storage settings
- [x] Add graph stats and vector metrics endpoints to worker service
- [x] Enhance UI sidebar with advanced metrics display and graph visualization
- [x] Optimize struct field alignment throughout codebase for memory efficiency
- [x] Update documentation with LEANN Phase 2 features and performance benefits
- [x] Add tree-sitter dependency for AST parsing

internal/worker/sse/broadcaster.go

@@ -19,10 +19,10 @@ const (
 
 // Client represents a connected SSE client.
 type Client struct {
-	ID      string
 	Writer  http.ResponseWriter
 	Flusher http.Flusher
 	Done    chan struct{}
+	ID      string
 }
 
 // Broadcaster manages SSE client connections and message broadcasting.

internal/worker/sse/broadcaster_test.go

@@ -256,8 +256,8 @@ func TestHandleSSE(t *testing.T) {
 // TestBroadcastJSON tests broadcasting various JSON types.
 func TestBroadcastJSON(t *testing.T) {
 	tests := []struct {
-		name    string
 		data    interface{}
+		name    string
 		wantErr bool
 	}{
 		{