✨ 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/consumer_core.go

@@ -0,0 +1,52 @@
+package nats
+
+import (
+	"caatsm/internal/app"
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/nats-io/nats.go"
+	"go.uber.org/zap"
+)
+
+// startCore starts the Core NATS consumer loop.
+func (c *Consumer) startCore(ctx context.Context) error {
+	queueGroup := c.cfg.Subscription.QueueGroup
+	if queueGroup == "" {
+		queueGroup = c.consumerName
+	}
+
+	handler := func(msg *nats.Msg) {
+		if err := c.processMessage(ctx, msg); err != nil {
+			isPermanent := app.IsPermanent(err)
+			c.logger.Error("Failed to process message (core mode)",
+				zap.String("subject", msg.Subject),
+				zap.Error(err),
+				zap.Bool("permanent", isPermanent),
+			)
+		}
+	}
+
+	sub, err := c.conn.QueueSubscribe(c.subject, queueGroup, handler)
+	if err != nil {
+		return fmt.Errorf("failed to subscribe to %s: %w", c.subject, err)
+	}
+	if err := c.conn.Flush(); err != nil {
+		return fmt.Errorf("failed to flush NATS connection: %w", err)
+	}
+
+	c.logger.Info("Started core NATS subscription",
+		zap.String("subject", c.subject),
+		zap.String("queue_group", queueGroup),
+	)
+
+	<-ctx.Done()
+	c.logger.Info("Stopping core NATS consumer", zap.Error(ctx.Err()))
+
+	if err := sub.Drain(); err != nil && !errors.Is(err, nats.ErrConnectionClosed) {
+		return fmt.Errorf("failed to drain core subscription: %w", err)
+	}
+
+	return ctx.Err()
+}