Fix: Configure quarkus.http.root-path for proper Swagger UI routing

- Added quarkus.http.root-path=/btpxpress in production config
- Removed custom Swagger UI files (index.html, swagger-initializer.js)
- Backend now knows it's served under /btpxpress context path
- Swagger UI will correctly generate URLs like /btpxpress/openapi

IMPORTANT: Ingress configuration must be updated to NOT use rewrite-target
The Ingress should pass requests to backend with full path preserved:
  https://api.lions.dev/btpxpress/openapi -> http://backend:8080/btpxpress/openapi

This is the proper solution instead of using rewrite-target which breaks
context-aware applications like Swagger UI.

src/main/resources/application-prod.properties

@@ -19,7 +19,9 @@ quarkus.hibernate-orm.log.bind-parameters=false
 # Serveur HTTP
 quarkus.http.port=${SERVER_PORT:8080}
 quarkus.http.host=0.0.0.0
-# Note: root-path removed - Ingress handles /btpxpress routing with rewrite-target
+quarkus.http.root-path=/btpxpress
+# Note: Backend is aware of the /btpxpress context path
+# Ingress should NOT use rewrite-target to preserve the full path
 
 # CORS Configuration pour production
 quarkus.http.cors=true