feat: add MACP event bridge — watcher, webhook, Discord formatter

bin/mosaic-macp

@@ -16,6 +16,7 @@ Usage:
   mosaic macp status [--task-id TASK-001]
   mosaic macp drain
   mosaic macp history [--task-id TASK-001]
+  mosaic macp watch [--webhook] [--once]
 USAGE
 }
 
@@ -193,6 +194,71 @@ for line in events_path.read_text(encoding="utf-8").splitlines():
 PY
 }
 
+watch_events() {
+  require_repo
+  local webhook_enabled="false"
+  local run_once="false"
+  while [[ $# -gt 0 ]]; do
+    case "$1" in
+      --webhook) webhook_enabled="true"; shift ;;
+      --once) run_once="true"; shift ;;
+      -h|--help) usage; exit 0 ;;
+      *) echo "[mosaic-macp] unknown watch option: $1" >&2; exit 1 ;;
+    esac
+  done
+
+  python3 - "$repo_root" "$config_path" "$events_path" "$orch_dir/event_cursor.json" "$webhook_enabled" "$run_once" <<'PY'
+import json
+import pathlib
+import sys
+
+repo_root = pathlib.Path(sys.argv[1]).resolve()
+config_path = pathlib.Path(sys.argv[2]).resolve()
+events_path = pathlib.Path(sys.argv[3]).resolve()
+cursor_path = pathlib.Path(sys.argv[4]).resolve()
+webhook_flag = sys.argv[5].lower() == "true"
+run_once = sys.argv[6].lower() == "true"
+
+events_dir = repo_root / "tools" / "orchestrator-matrix" / "events"
+if str(events_dir) not in sys.path:
+    sys.path.insert(0, str(events_dir))
+
+from discord_formatter import format_event
+from event_watcher import EventWatcher
+from webhook_adapter import create_webhook_callback
+
+config = {}
+if config_path.exists():
+    config = json.loads(config_path.read_text(encoding="utf-8"))
+
+macp = dict(config.get("macp") or {})
+watcher = EventWatcher(
+    events_path=events_path,
+    cursor_path=cursor_path,
+    poll_interval=float(macp.get("watch_poll_interval_seconds") or 2.0),
+)
+
+def print_callback(event: dict) -> None:
+    rendered = format_event(event)
+    if rendered:
+        print(rendered)
+
+watcher.on([], print_callback)
+
+webhook_config = dict(macp.get("webhook") or {})
+if webhook_flag and bool(webhook_config.get("enabled", False)):
+    watcher.on(list(webhook_config.get("event_filter") or []), create_webhook_callback(config))
+elif webhook_flag:
+    print("[mosaic-macp] webhook requested but disabled in config", file=sys.stderr)
+
+if run_once:
+    processed = watcher.poll_once()
+    print(f"[mosaic-macp] processed_events={len(processed)}")
+else:
+    watcher.run()
+PY
+}
+
 subcommand="${1:-help}"
 if [[ $# -gt 0 ]]; then
   shift
@@ -203,6 +269,7 @@ case "$subcommand" in
   status) status_tasks "$@" ;;
   drain) drain_tasks "$@" ;;
   history) history_tasks "$@" ;;
+  watch) watch_events "$@" ;;
   help|-h|--help|"") usage ;;
   *)
     echo "[mosaic-macp] unknown subcommand: $subcommand" >&2