Fix validation script: correct expected statuses, remove internal endpoints, add status mismatch catch-all

- Change DELETE /templates/{templateID} cleanup expected status from 200 to 204
- Remove POST /init test (internal endpoint, not in public spec)
- Remove unauthenticated 401 tests to avoid load balancer rate limiting
- Use account-owned template alias instead of hardcoded 'base' for alias test
- Send no-op Update to process instead of PTY resize (avoids 500 on non-PTY process)
- Add post-processing catch-all that flags any tested endpoint with unexpected status code

Author: beran-t