fix(config): Improve config-manager.js for MCP server integration

- Fixed MCP server initialization warnings by refactoring config-manager.js to handle missing project roots silently during startup

- Added project root tracking (loadedConfigRoot) to improve config caching and prevent unnecessary reloads

- Modified _loadAndValidateConfig to return defaults without warnings when no explicitRoot provided

- Improved getConfig to only update cache when loading config with a specific project root

- Ensured warning messages still appear when explicitly specified roots have missing/invalid configs

- Prevented console output during MCP startup that was causing JSON parsing errors

- Verified parse_prd and other MCP tools still work correctly with the new config loading approach.

- Replaces test perplexity api key in mcp.json and rolls it. It's invalid now.

scripts/modules/ai-services-unified.js

@@ -209,7 +209,7 @@ async function _unifiedServiceRunner(serviceType, params) {
 		let providerName, modelId, apiKey, roleParams, providerFnSet, providerApiFn;
 
 		try {
-			log('info', `Attempting service call with role: ${currentRole}`);
+			log('info', `New AI service call with role: ${currentRole}`);
 
 			// --- Corrected Config Fetching ---
 			// 1. Get Config: Provider, Model, Parameters for the current role