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.

pkg/services/identity.go

@@ -30,6 +30,9 @@ type IdentityServiceClient interface {
 
 	// ResetPassword resets a user's password using a reset token.
 	ResetPassword(ctx context.Context, token, newPassword string) error
+
+	// VerifyPassword verifies a user's password and returns the user if valid.
+	VerifyPassword(ctx context.Context, email, password string) (*User, error)
 }
 
 // User represents a user in the system.