Fix: CORS and API base URL for music create in staging

- Update CORS config to allow all origins (wildcard first) for better staging support
- Change API fetch base URL from absolute to relative (/) to prevent mixed content blocking
- Add detailed logging in music create page for better debugging
- Update .env.example with better NEXT_PUBLIC_BASE_URL documentation
- Add MUSIK_CREATE_ANALYSIS.md with comprehensive error analysis

Fixes ERR_BLOCKED_BY_CLIENT error when creating music in staging environment

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

src/lib/api-fetch.ts

@@ -1,8 +1,9 @@
 import { AppServer } from '@/app/api/[[...slugs]]/route'
 import { treaty } from '@elysiajs/eden'
 
-// const BASE_URL = process.env.NEXT_PUBLIC_BASE_URL || 'localhost:3000'
-const BASE_URL = process.env.NEXT_PUBLIC_BASE_URL || 'http://localhost:3000'
+// Use relative URL '/' for better deployment flexibility
+// This allows the API to work correctly in both development and staging/production
+const BASE_URL = process.env.NEXT_PUBLIC_BASE_URL || '/'
 
 const ApiFetch = treaty<AppServer>(BASE_URL)