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

infra/all-in-one-gateway/.env.example

@@ -0,0 +1,24 @@
+# ============================================================================
+# DAARION All-in-One Gateway — Environment Variables
+# ============================================================================
+
+# Database
+DATABASE_URL=postgres://microdao:microdao@postgres:5432/microdao
+
+# Cache
+REDIS_URL=redis://redis:6379/0
+
+# Message Bus
+NATS_URL=nats://nats:4222
+
+# Matrix
+SYNAPSE_SERVER_NAME=localhost
+
+# RAG Service
+RAG_MODEL_NAME=BAAI/bge-m3
+
+# Notification Service
+NOTIFY_FROM_EMAIL=noreply@localhost
+
+# PostgreSQL (для docker-compose)
+POSTGRES_PASSWORD=postgres