✨ 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.

configs/config.dev.toml

@@ -1,5 +1,20 @@
 [nats]
 url = "nats://localhost:4222"
+# mode: "core" (default for dev) or "jetstream" (recommended for production)
+#   - "core": Uses Core NATS for simple pub/sub messaging with:
+#     * No message persistence (messages lost if consumer offline)
+#     * No ACK mechanism (fire-and-forget delivery)
+#     * No automatic retry on processing failures
+#     * Queue groups for load balancing only
+#     * Suitable for development/testing or real-time scenarios where message loss is acceptable
+#     * Recommended for local development and testing
+#   - "jetstream": Uses NATS JetStream for persistent message streaming with:
+#     * Message persistence and replay capability
+#     * ACK/NAK mechanism for guaranteed delivery
+#     * Automatic retry with configurable backoff
+#     * Dead-letter queue (DLQ) support
+#     * Batch processing and consumer monitoring
+#     * Recommended for production environments
 mode = "core"
 client = "serial-client"
 cluster = "tele-cluster"
@@ -7,21 +22,45 @@ stream = "TELEGRAM"
 consumer = "telegram-consumer"
 
 [nats.stream_limits]
+# Stream retention and storage limits (only applies when mode = "jetstream")
+# max_msgs: Maximum number of messages to keep in the stream (0 = unlimited)
 max_msgs = 100000
+# max_bytes: Maximum total size of messages in bytes (0 = unlimited, 67108864 = 64MB)
 max_bytes = 67108864
+# max_age: Maximum age of messages before automatic deletion (e.g., "24h", "7d")
 max_age = "24h"
+# discard: What to do when limits are reached: "old" (delete oldest) or "new" (reject new)
 discard = "old"
+# storage: "file" (persistent to disk) or "memory" (ephemeral, faster but lost on restart)
 storage = "file"
+# replicas: Number of stream replicas for high availability (1 = single node, 3+ for production cluster)
 replicas = 1
 
 [nats.consumer_rules]
+# Consumer delivery and retry rules (only applies when mode = "jetstream")
+# max_deliver: Maximum number of delivery attempts before giving up (0 = unlimited)
 max_deliver = 5
+# ack_wait: Time to wait for ACK before redelivering message (e.g., "30s", "2m")
 ack_wait = "30s"
+# max_ack_pending: Maximum number of unacknowledged messages before pausing delivery
 max_ack_pending = 1024
+# deliver_policy: When to start delivering messages:
+#   - "all": Deliver all messages from the stream
+#   - "new": Only deliver new messages after consumer creation
+#   - "last": Deliver only the last message
+#   - "last_per_subject": Deliver last message per subject
+#   - "sequence": Start from a specific sequence (requires start_sequence)
+#   - "time": Start from a specific time (requires start_time in RFC3339 format)
 deliver_policy = "all"
+# replay_policy: How to replay messages: "instant" (as fast as possible) or "original" (preserve timing)
 replay_policy = "instant"
+# backoff: Array of delays between retry attempts (e.g., ["5s", "30s", "2m"])
+#   First retry waits 5s, second waits 30s, third and beyond wait 2m
 backoff = ["5s", "30s", "2m"]
+# start_sequence: Starting sequence number (only used when deliver_policy = "sequence")
 start_sequence = 0
+# start_time: Starting time in RFC3339 format (only used when deliver_policy = "time")
+#   Example: "2024-11-15T08:00:00Z"
 start_time = ""
 
 [subscription]
@@ -43,8 +82,12 @@ max_conns = 10
 min_conns = 2
 
 [app]
+# Batch processing configuration (applies to both core and jetstream modes)
+# batch_size: Number of messages to fetch in each batch (JetStream pull batch size)
 batch_size = 50
+# batch_timeout: Maximum time to wait when fetching a batch (e.g., "2s")
 batch_timeout = "2s"
+# monitor_interval: How often to emit consumer statistics and metrics
 monitor_interval = "30s"
 
 [log]
@@ -85,5 +128,8 @@ write_timeout = "5s"
 health_timeout = "2s"
 
 [dlq]
-enabled = true
-subject = "caatsm.dlq"
+# Dead-Letter Queue configuration (only applies when mode = "jetstream")
+# enabled: Enable DLQ routing for poison messages (messages that fail after max_deliver attempts)
+enabled = false  # Set to true when switching to JetStream mode
+# subject: NATS subject where failed messages will be published for manual inspection
+subject = "caatsm.dlq"