✨ Add repository guidelines and enhance documentation for project structure, build commands, coding standards, and testing practices. Introduce AGENTS.md for contributor guidance, update README.md to reference new guidelines, and improve configuration documentation for NATS modes. Update Makefile and Taskfile with clearer run commands and requirements for development and production modes. Add production deployment guide and improve logging configuration for better observability.

internal/infra/nats/publisher.go

@@ -20,12 +20,17 @@ type Publisher struct {
 	logger *zap.Logger
 }
 
-// ProvidePublisher creates a NATS publisher
+// ProvidePublisher creates a NATS publisher.
+// When js is nil (core mode), returns a CorePublisher that uses plain NATS.
 func ProvidePublisher(
 	js nats.JetStreamContext,
+	nc *nats.Conn,
 	cfg *config.Config,
 	logger *zap.Logger,
 ) (port.Publisher, error) {
+	if js == nil {
+		return ProvideCorePublisher(nc, cfg, logger)
+	}
 	return &Publisher{
 		js:     js,
 		cfg:    cfg,
@@ -33,6 +38,63 @@ func ProvidePublisher(
 	}, nil
 }
 
+// CorePublisher publishes messages to plain NATS (non-JetStream)
+type CorePublisher struct {
+	conn   *nats.Conn
+	cfg    *config.Config
+	logger *zap.Logger
+}
+
+// ProvideCorePublisher creates a NATS publisher for core mode
+func ProvideCorePublisher(
+	conn *nats.Conn,
+	cfg *config.Config,
+	logger *zap.Logger,
+) (port.Publisher, error) {
+	return &CorePublisher{
+		conn:   conn,
+		cfg:    cfg,
+		logger: logger,
+	}, nil
+}
+
+// Publish publishes a message using plain NATS
+func (p *CorePublisher) Publish(message interface{}) error {
+	topic := p.cfg.Publisher.Topic
+	if topic == "" {
+		p.logger.Error("publisher topic is not configured")
+		return fmt.Errorf("publisher topic is not configured")
+	}
+
+	// Marshal message to JSON
+	messageBytes, err := json.Marshal(message)
+	if err != nil {
+		p.logger.Error("failed to marshal message",
+			zap.String("topic", topic),
+			zap.Error(err),
+		)
+		return fmt.Errorf("failed to marshal message: %w", err)
+	}
+
+	// Publish to plain NATS
+	err = p.conn.Publish(topic, messageBytes)
+	if err != nil {
+		p.logger.Error("failed to publish message",
+			zap.String("topic", topic),
+			zap.Int("message_size", len(messageBytes)),
+			zap.Error(err),
+		)
+		return fmt.Errorf("failed to publish message: %w", err)
+	}
+
+	p.logger.Debug("Published message",
+		zap.String("topic", topic),
+		zap.Int("size", len(messageBytes)),
+	)
+
+	return nil
+}
+
 // Publish publishes a message
 func (p *Publisher) Publish(message interface{}) error {
 	topic := p.cfg.Publisher.Topic