feat(auth): Complete Auth Service implementation and fix Consul health checks

- Add VerifyPassword RPC to Identity Service
  - Added to proto file and generated code
  - Implemented in Identity Service gRPC server
  - Added to Identity Service client interface and gRPC client

- Complete RefreshToken implementation
  - Store refresh tokens in database using RefreshToken entity
  - Validate refresh tokens with expiration checking
  - Revoke refresh tokens on logout and token rotation

- Integrate Authz Service for role retrieval
  - Added AuthzServiceClient to Auth Service
  - Get user roles during login and token refresh
  - Gracefully handle Authz Service failures

- Require JWT secret in configuration
  - Removed default secret fallback
  - Service fails to start if JWT secret is not configured

- Fix Consul health checks for Docker
  - Services now register with Docker service names (e.g., audit-service)
  - Allows Consul (in Docker) to reach services via Docker DNS
  - Health checks use gRPC service names instead of localhost

This completes all TODOs in auth_service_fx.go and fixes the Consul
health check failures in Docker environments.

api/proto/identity.proto

@@ -29,6 +29,9 @@ service IdentityService {
   
   // ResetPassword resets a user's password using a reset token.
   rpc ResetPassword(ResetPasswordRequest) returns (ResetPasswordResponse);
+  
+  // VerifyPassword verifies a user's password.
+  rpc VerifyPassword(VerifyPasswordRequest) returns (VerifyPasswordResponse);
 }
 
 // User represents a user in the system.
@@ -132,3 +135,14 @@ message ResetPasswordResponse {
   bool success = 1;
 }
 
+// VerifyPasswordRequest contains email and password.
+message VerifyPasswordRequest {
+  string email = 1;
+  string password = 2;
+}
+
+// VerifyPasswordResponse contains the user if password is valid.
+message VerifyPasswordResponse {
+  User user = 1;
+}
+