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.

cmd/identity-service/identity_service_fx.go

@@ -355,6 +355,26 @@ func (s *identityServerImpl) ResetPassword(ctx context.Context, req *identityv1.
 	return &identityv1.ResetPasswordResponse{Success: true}, nil
 }
 
+// VerifyPassword verifies a user's password.
+func (s *identityServerImpl) VerifyPassword(ctx context.Context, req *identityv1.VerifyPasswordRequest) (*identityv1.VerifyPasswordResponse, error) {
+	u, err := s.service.verifyPassword(ctx, req.Email, req.Password)
+	if err != nil {
+		return nil, status.Errorf(codes.Unauthenticated, "invalid credentials: %v", err)
+	}
+	return &identityv1.VerifyPasswordResponse{
+		User: &identityv1.User{
+			Id:            u.ID,
+			Email:         u.Email,
+			Username:      u.Username,
+			FirstName:     u.FirstName,
+			LastName:      u.LastName,
+			EmailVerified: u.Verified,
+			CreatedAt:     u.CreatedAt.Unix(),
+			UpdatedAt:     u.UpdatedAt.Unix(),
+		},
+	}, nil
+}
+
 // provideIdentityService creates the identity service and gRPC server.
 func provideIdentityService() fx.Option {
 	return fx.Options(