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

pkg/models/session.go

@@ -17,29 +17,29 @@ const (
 
 // SDKSession represents a Claude Code session tracked by the memory system.
 type SDKSession struct {
-	ID               int64          `db:"id" json:"id"`
 	ClaudeSessionID  string         `db:"claude_session_id" json:"claude_session_id"`
-	SDKSessionID     sql.NullString `db:"sdk_session_id" json:"sdk_session_id,omitempty"`
 	Project          string         `db:"project" json:"project"`
-	UserPrompt       sql.NullString `db:"user_prompt" json:"user_prompt,omitempty"`
-	WorkerPort       sql.NullInt64  `db:"worker_port" json:"worker_port,omitempty"`
-	PromptCounter    int64          `db:"prompt_counter" json:"prompt_counter"`
 	Status           SessionStatus  `db:"status" json:"status"`
 	StartedAt        string         `db:"started_at" json:"started_at"`
-	StartedAtEpoch   int64          `db:"started_at_epoch" json:"started_at_epoch"`
+	SDKSessionID     sql.NullString `db:"sdk_session_id" json:"sdk_session_id,omitempty"`
+	UserPrompt       sql.NullString `db:"user_prompt" json:"user_prompt,omitempty"`
 	CompletedAt      sql.NullString `db:"completed_at" json:"completed_at,omitempty"`
+	WorkerPort       sql.NullInt64  `db:"worker_port" json:"worker_port,omitempty"`
 	CompletedAtEpoch sql.NullInt64  `db:"completed_at_epoch" json:"completed_at_epoch,omitempty"`
+	ID               int64          `db:"id" json:"id"`
+	PromptCounter    int64          `db:"prompt_counter" json:"prompt_counter"`
+	StartedAtEpoch   int64          `db:"started_at_epoch" json:"started_at_epoch"`
 }
 
 // ActiveSession represents an in-memory active session being processed.
 type ActiveSession struct {
-	SessionDBID            int64
+	StartTime              time.Time
 	ClaudeSessionID        string
 	SDKSessionID           string
 	Project                string
 	UserPrompt             string
+	SessionDBID            int64
 	LastPromptNumber       int
-	StartTime              time.Time
 	CumulativeInputTokens  int64
 	CumulativeOutputTokens int64
 }