fix: resolve homepage host validation issue using TDD approach

- Created test to verify homepage host validation issue
- Identified that HOMEPAGE_ALLOWED_HOSTS environment variable was needed
- Updated homepage Docker Compose with proper allowed hosts setting
- Added 'localhost:4000,127.0.0.1:4000' to HOMEPAGE_ALLOWED_HOSTS
- All tests now pass with no host validation errors
- Updated prompt to emphasize TDD approach for all changes
- Implemented atomic testing approach for immediate validation

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

collab/SupportStack/BuildTheStack

@@ -22,6 +22,10 @@ Create a proof of concept with docker-socket-proxy, homepage, and wakaapi compon
 - 100% test pass requirement
 - Component-by-component development approach
 - Complete one component before moving to the next
+- Apply TDD for every change, no matter how surgical
+- Test changes right after implementation as atomically as possible
+- Each fix or modification should be accompanied by a specific test to verify the issue
+- Ensure all changes are validated immediately after implementation
 
 ## MVP Component Development Sequence (Test Run)
 1. **MVP**: docker-socket-proxy, homepage, wakaapi (each must fully satisfy Definition of Done before proceeding)