fix: Explicitly import Observable mixin in MCP lifecycle services (#9831)

Author: tobiu

ai/mcp/server/knowledge-base/services/DatabaseLifecycleService.mjs

@@ -2,6 +2,7 @@ import {spawn}  from 'child_process';
 import aiConfig from '../config.mjs';
 import logger   from '../logger.mjs';
 import Base     from '../../../../../src/core/Base.mjs';
+import Observable from '../../../../../src/core/Observable.mjs';
 
 /**
  * @summary Manages the lifecycle of the ChromaDB process for the Knowledge Base.

ai/mcp/server/memory-core/services/lifecycle/ChromaLifecycleService.mjs

@@ -2,6 +2,7 @@ import { spawn } from 'child_process';
 import aiConfig from '../../config.mjs';
 import logger from '../../logger.mjs';
 import Base from '../../../../../../src/core/Base.mjs';
+import Observable from '../../../../../../src/core/Observable.mjs';
 
 /**
  * @summary Orchestrates the daemon lifecycle specifically for the ChromaDB backend engine.