Add presence heartbeat to keep bot shown as online

Adds a background asyncio.Task that calls set_presence("online") every
60 seconds to keep the homeserver presence status fresh. On startup the
bot sets itself online and spawns the heartbeat; on shutdown the task is
cancelled and presence is set to offline before closing the client.

https://claude.ai/code/session_01Nu3N2okrfJV3meatEmYdrB

gaming_deals_bot/matrix_client.py

@@ -1,11 +1,14 @@
 """Matrix client wrapper for sending deal messages."""
 
+import asyncio
 import logging
 
-from nio import AsyncClient, RoomSendError
+from nio import AsyncClient, PresenceSetError, RoomSendError
 
 logger = logging.getLogger(__name__)
 
+PRESENCE_HEARTBEAT_INTERVAL = 60  # seconds
+
 
 class MatrixDealsClient:
     def __init__(
@@ -19,6 +22,7 @@ class MatrixDealsClient:
         self._client = AsyncClient(homeserver_url, user_id)
         self._client.access_token = access_token
         self._client.user_id = user_id
+        self._heartbeat_task: asyncio.Task | None = None
 
     async def send_deal(self, plain_text: str, html: str) -> bool:
         """Send a deal message to the configured room.
@@ -68,5 +72,49 @@ class MatrixDealsClient:
             logger.error("Matrix send error: %s", exc)
             return False
 
+    async def set_presence(self, presence: str) -> bool:
+        """Set the bot's presence status on the homeserver.
+
+        Returns True on success, False on failure.
+        """
+        try:
+            resp = await self._client.set_presence(presence)
+            if isinstance(resp, PresenceSetError):
+                logger.error("Failed to set presence to %s: %s", presence, resp.message)
+                return False
+            logger.debug("Presence set to %s", presence)
+            return True
+        except Exception as exc:
+            logger.error("Presence set error: %s", exc)
+            return False
+
+    async def start_presence_heartbeat(self):
+        """Set presence to online and spawn a background task to keep it alive."""
+        await self.set_presence("online")
+        self._heartbeat_task = asyncio.create_task(self._presence_heartbeat_loop())
+        logger.info("Presence heartbeat started (every %ds)", PRESENCE_HEARTBEAT_INTERVAL)
+
+    async def _presence_heartbeat_loop(self):
+        """Re-send 'online' presence every PRESENCE_HEARTBEAT_INTERVAL seconds."""
+        try:
+            while True:
+                await asyncio.sleep(PRESENCE_HEARTBEAT_INTERVAL)
+                await self.set_presence("online")
+        except asyncio.CancelledError:
+            pass
+
+    async def stop_presence_heartbeat(self):
+        """Cancel the heartbeat task and set presence to offline."""
+        if self._heartbeat_task is not None:
+            self._heartbeat_task.cancel()
+            try:
+                await self._heartbeat_task
+            except asyncio.CancelledError:
+                pass
+            self._heartbeat_task = None
+        await self.set_presence("offline")
+        logger.info("Presence heartbeat stopped, set to offline")
+
     async def close(self):
+        await self.stop_presence_heartbeat()
         await self._client.close()