feat: add __main__.py entry point

ns8_backup_monitor/__main__.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+"""
+__main__.py - Entry point for ns8-backup-monitor.
+
+Usage:
+    python3 -m ns8_backup_monitor
+    python3 -m ns8_backup_monitor --config /etc/ns8-backup-monitor/config.yml
+"""
+
+import argparse
+import sys
+
+from .utils import load_config, setup_logging
+from .receiver import run_server
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description="NS8 Backup Monitor - Alertmanager webhook receiver and correlator"
+    )
+    parser.add_argument(
+        "--config", "-c",
+        metavar="PATH",
+        help="Path to config.yml (default: auto-detect)",
+        default=None,
+    )
+    args = parser.parse_args()
+
+    try:
+        config = load_config(args.config)
+    except FileNotFoundError as e:
+        print(f"ERROR: {e}", file=sys.stderr)
+        sys.exit(1)
+
+    setup_logging(config)
+
+    run_server(config)
+
+
+if __name__ == "__main__":
+    main()