feat(graph): add observation graph with hybrid vector storage

- [x] Add golangci.yml configuration with fieldalignment linter
- [x] Implement observation graph structure with edge detection
- [x] Add LEANN-inspired hybrid vector storage with hub threshold
- [x] Implement graph-aware search with selective recomputation
- [x] Add auto-tuner for dynamic hub threshold adjustment
- [x] Add graph and vector metrics tracking and reporting
- [x] Extend configuration for graph parameters
- [x] Add graph rebuild background service with periodic updates
- [x] Add HTTP endpoints for graph stats and vector metrics
- [x] Update UI with advanced metrics sidebar panel
- [x] Implement AST-aware code chunking for Go, Python, TypeScript

internal/vector/interface.go

@@ -0,0 +1,42 @@
+// Package vector provides common interfaces for vector storage implementations
+package vector
+
+import (
+	"context"
+
+	"github.com/lukaszraczylo/claude-mnemonic/internal/vector/sqlitevec"
+)
+
+// Client defines the interface for vector storage operations.
+// Both sqlitevec.Client and hybrid.Client implement this interface.
+type Client interface {
+	// AddDocuments adds documents with their embeddings to the vector store
+	AddDocuments(ctx context.Context, docs []sqlitevec.Document) error
+
+	// DeleteDocuments removes documents by their IDs
+	DeleteDocuments(ctx context.Context, ids []string) error
+
+	// Query performs a vector similarity search
+	Query(ctx context.Context, query string, limit int, where map[string]any) ([]sqlitevec.QueryResult, error)
+
+	// IsConnected checks if the vector store is available
+	IsConnected() bool
+
+	// Close releases resources
+	Close() error
+
+	// Count returns the total number of vectors in the store
+	Count(ctx context.Context) (int64, error)
+
+	// ModelVersion returns the current embedding model version
+	ModelVersion() string
+
+	// NeedsRebuild checks if vectors need to be rebuilt due to model version change
+	NeedsRebuild(ctx context.Context) (bool, string)
+
+	// GetStaleVectors returns doc_ids of vectors with mismatched or null model versions
+	GetStaleVectors(ctx context.Context) ([]sqlitevec.StaleVectorInfo, error)
+
+	// DeleteVectorsByDocIDs removes vectors by their doc_ids
+	DeleteVectorsByDocIDs(ctx context.Context, docIDs []string) error
+}