feat: Add presence heartbeat for Matrix online status

- matrix-gateway: POST /internal/matrix/presence/online endpoint
- usePresenceHeartbeat hook with activity tracking
- Auto away after 5 min inactivity
- Offline on page close/visibility change
- Integrated in MatrixChatRoom component

scripts/stop-phase4.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+# Stop DAARION Phase 4 Services
+
+echo "🛑 Stopping DAARION Phase 4 services..."
+
+docker-compose -f docker-compose.phase4.yml down
+
+echo "✅ Phase 4 services stopped"
+
+
+
+