MAJOR: Complete OIDC migration - Remove JWT custom auth, integrate Keycloak OIDC

- Remove quarkus-smallrye-jwt extension
- Delete JwtService, AuthServiceImpl, AuthService interface
- Replace AuthResource with OIDC-based implementation
- Update SecurityService to use SecurityIdentity instead of JWT
- Configure OIDC with Keycloak (bearer-only backend)
- Add PostgreSQL configuration
- Update entity relationships and database migrations
- Remove JWT-related tests and configurations

BREAKING CHANGE: Authentication now requires Keycloak OIDC tokens

pom.xml

@@ -85,7 +85,7 @@
         </dependency>
         <dependency>
             <groupId>io.quarkus</groupId>
-            <artifactId>quarkus-smallrye-jwt</artifactId>
+            <artifactId>quarkus-oidc</artifactId>
         </dependency>
 
         <!-- Validation -->