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/sdk/processor.go

@@ -31,15 +31,14 @@ type SyncSummaryFunc func(summary *models.SessionSummary)
 
 // Processor handles SDK agent processing of observations and summaries using Claude Code CLI.
 type Processor struct {
-	claudePath          string
-	model               string
 	observationStore    *gorm.ObservationStore
 	summaryStore        *gorm.SummaryStore
 	broadcastFunc       BroadcastFunc
 	syncObservationFunc SyncObservationFunc
 	syncSummaryFunc     SyncSummaryFunc
-	// Semaphore to limit concurrent Claude CLI calls (prevents API overload)
-	sem chan struct{}
+	sem                 chan struct{}
+	claudePath          string
+	model               string
 }
 
 // SetBroadcastFunc sets the broadcast callback for SSE events.