**feat(docs): add comprehensive Search and Metadata Guide with metadata handling updates**

- **Documentation Additions**:
  - Introduced `SEARCH_AND_METADATA_GUIDE.md` to provide an in-depth guide on Brainy's search and metadata retrieval system:
    - Detailed explanation of search workflows, metadata structures (`GraphNoun`, `GraphVerb`), and core components like `SearchResult`.
    - Usage examples showcasing search queries, filtering by noun/verb types, and advanced features like multi-modal search.
    - Included performance tips on caching, HNSW indexing, lazy loading, and augmentation pipeline.

- **Storage System Updates**:
  - Enhanced memory and file storage adapters to support dedicated noun and verb metadata handling:
    - Added methods `saveN

src/storage/adapters/memoryStorage.ts

@@ -18,6 +18,8 @@ export class MemoryStorage extends BaseStorage {
   private nouns: Map<string, HNSWNoun> = new Map()
   private verbs: Map<string, GraphVerb> = new Map()
   private metadata: Map<string, any> = new Map()
+  private nounMetadata: Map<string, any> = new Map()
+  private verbMetadata: Map<string, any> = new Map()
   private statistics: StatisticsData | null = null
 
   constructor() {
@@ -557,6 +559,44 @@ export class MemoryStorage extends BaseStorage {
     return JSON.parse(JSON.stringify(metadata))
   }
 
+  /**
+   * Save noun metadata to storage
+   */
+  public async saveNounMetadata(id: string, metadata: any): Promise<void> {
+    this.nounMetadata.set(id, JSON.parse(JSON.stringify(metadata)))
+  }
+
+  /**
+   * Get noun metadata from storage
+   */
+  public async getNounMetadata(id: string): Promise<any | null> {
+    const metadata = this.nounMetadata.get(id)
+    if (!metadata) {
+      return null
+    }
+
+    return JSON.parse(JSON.stringify(metadata))
+  }
+
+  /**
+   * Save verb metadata to storage
+   */
+  public async saveVerbMetadata(id: string, metadata: any): Promise<void> {
+    this.verbMetadata.set(id, JSON.parse(JSON.stringify(metadata)))
+  }
+
+  /**
+   * Get verb metadata from storage
+   */
+  public async getVerbMetadata(id: string): Promise<any | null> {
+    const metadata = this.verbMetadata.get(id)
+    if (!metadata) {
+      return null
+    }
+
+    return JSON.parse(JSON.stringify(metadata))
+  }
+
   /**
    * Clear all data from storage
    */
@@ -564,6 +604,8 @@ export class MemoryStorage extends BaseStorage {
     this.nouns.clear()
     this.verbs.clear()
     this.metadata.clear()
+    this.nounMetadata.clear()
+    this.verbMetadata.clear()
     this.statistics = null
   }