Refactor contextHook to simplify recent summaries retrieval and output formatting

- Updated contextHook to query session_summaries directly instead of using sdk_sessions table.
- Removed unnecessary complexity in output formatting, focusing on recent summaries for the project.
- Enhanced file reading and modification tracking by parsing observations directly.
- Made the database connection public in SessionStore for easier access.

src/services/sqlite/SessionStore.ts

@@ -7,7 +7,7 @@ import { logger } from '../../utils/logger.js';
  * Provides simple, synchronous CRUD operations for session-based memory
  */
 export class SessionStore {
-  private db: Database.Database;
+  public db: Database.Database;
 
   constructor() {
     ensureDir(DATA_DIR);