Implement From<CorsSettings> for Cors trait to configure CORS middleware
with production-ready security validation.
- Move CorsSettings to backend/src/settings/cors.rs module
- Validate wildcard + credentials constraint (browser security policy)
- Configure allowed methods, headers, credentials, and max_age
- Add structured logging for CORS configuration
- Move tests from settings/mod.rs and startup.rs to cors module
Ref: T014
Lucien Cartier-Tilet
f4e2fb4a17
