fix(update): pass projectRoot through update command flow

Modified ai-services-unified.js, update.js tool, and update-tasks.js direct function to correctly pass projectRoot. This enables the .env file API key fallback mechanism for the update command when running via MCP, ensuring consistent key resolution with the CLI context.

mcp-server/src/tools/update.js

@@ -70,7 +70,8 @@ export function registerUpdateTool(server) {
 						tasksJsonPath: tasksJsonPath,
 						from: args.from,
 						prompt: args.prompt,
-						research: args.research
+						research: args.research,
+						projectRoot: rootFolder
 					},
 					log,
 					{ session }