fix(consul): Fix health checks for gRPC services in Docker

- Add gRPC health check support to Consul registry
  - Services are gRPC-only, not HTTP
  - Consul was trying HTTP health checks which failed
  - Now uses gRPC health checks via grpc.health.v1.Health service

- Update HealthCheckConfig to support both HTTP and gRPC
  - Add GRPC field for gRPC service name
  - Add UseGRPC flag to choose health check type
  - Default to gRPC for services (use_grpc: true in config)

- Fix service address registration in Docker
  - Services now register with Docker service name (e.g., auth-service)
  - Allows Consul to reach services via Docker network DNS
  - Falls back to localhost for local development

- Update default.yaml to enable gRPC health checks
  - Set use_grpc: true
  - Set grpc: grpc.health.v1.Health

This fixes services being deregistered from Consul due to failed
HTTP health checks. Services will now pass gRPC health checks.

internal/di/providers.go

@@ -218,8 +218,14 @@ func ProvideServiceRegistry() fx.Option {
 				healthCheckDeregisterAfter = 30 * time.Second
 			}
 			healthCheckHTTP := cfg.GetString("registry.consul.health_check.http")
-			if healthCheckHTTP == "" {
-				healthCheckHTTP = "/healthz"
+			healthCheckGRPC := cfg.GetString("registry.consul.health_check.grpc")
+			useGRPC := cfg.GetBool("registry.consul.health_check.use_grpc")
+			// Default to gRPC if not explicitly set (services are gRPC by default)
+			if !cfg.IsSet("registry.consul.health_check.use_grpc") {
+				useGRPC = true
+			}
+			if healthCheckGRPC == "" {
+				healthCheckGRPC = "grpc.health.v1.Health"
 			}
 
 			consulCfg.HealthCheck = consul.HealthCheckConfig{
@@ -227,6 +233,8 @@ func ProvideServiceRegistry() fx.Option {
 				Timeout:         healthCheckTimeout,
 				DeregisterAfter: healthCheckDeregisterAfter,
 				HTTP:            healthCheckHTTP,
+				GRPC:            healthCheckGRPC,
+				UseGRPC:         useGRPC,
 			}
 
 			return consul.NewRegistry(consulCfg)