feat: Always enable embeddings, remove enableEmbeddings config option

Testing showed semantic search produces significantly better results for
natural language queries that Claude writes. FTS alone often ranks
properties above their parent classes and misses conceptual matches.
Embeddings are now always on — the vector manager is created eagerly,
with model download and embedding generation still happening lazily.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/types.ts

@@ -462,9 +462,6 @@ export interface CodeGraphConfig {
   /** Whether to track call sites */
   trackCallSites: boolean;
 
-  /** Whether to compute embeddings for semantic search */
-  enableEmbeddings: boolean;
-
   /** Custom symbol patterns to extract */
   customPatterns?: {
     /** Name for this pattern group */
@@ -675,7 +672,6 @@ export const DEFAULT_CONFIG: CodeGraphConfig = {
   maxFileSize: 1024 * 1024, // 1MB
   extractDocstrings: true,
   trackCallSites: true,
-  enableEmbeddings: false,
 };
 
 // =============================================================================