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

services/living-map-service/adapters/usage_client.py

@@ -0,0 +1,40 @@
+"""
+Usage Engine Client Adapter
+Phase 9: Living Map
+"""
+from typing import Dict, Any
+from .base_client import BaseServiceClient
+import os
+
+class UsageClient(BaseServiceClient):
+    """Client for usage-engine"""
+    
+    def __init__(self):
+        base_url = os.getenv("USAGE_ENGINE_URL", "http://localhost:7013")
+        super().__init__(base_url)
+    
+    async def get_usage_summary(self, period_hours: int = 24) -> Dict[str, Any]:
+        """Get usage summary for period"""
+        result = await self.get_with_fallback(
+            "/internal/usage/summary",
+            fallback={
+                "total_llm_calls": 0,
+                "total_tokens": 0,
+                "period_hours": period_hours
+            },
+            params={"period_hours": period_hours}
+        )
+        return result
+    
+    async def get_agent_usage(self, agent_id: str) -> Dict[str, Any]:
+        """Get usage for specific agent"""
+        result = await self.get_with_fallback(
+            f"/internal/usage/agent/{agent_id}",
+            fallback={
+                "llm_calls_24h": 0,
+                "tokens_24h": 0,
+                "messages_24h": 0
+            }
+        )
+        return result
+