feat: add test validation command and improve environment variable handling

- Introduced a new command for validating tests, providing detailed instructions for running tests and fixing failures based on code changes.
- Updated the environment variable handling in the Claude provider to only allow explicitly defined variables, enhancing security and preventing leakage of sensitive information.
- Improved feature loading to handle errors more gracefully and load features concurrently, optimizing performance.
- Centralized port configuration for the Automaker application to prevent accidental termination of critical services.

libs/platform/src/config/ports.ts

@@ -0,0 +1,15 @@
+/**
+ * Centralized port configuration for AutoMaker
+ *
+ * These ports are reserved for the Automaker application and should never be
+ * killed or terminated by AI agents during feature implementation.
+ */
+
+/** Port for the static/UI server (Vite dev server) */
+export const STATIC_PORT = 3007;
+
+/** Port for the backend API server (Express + WebSocket) */
+export const SERVER_PORT = 3008;
+
+/** Array of all reserved Automaker ports */
+export const RESERVED_PORTS = [STATIC_PORT, SERVER_PORT] as const;