Stabilize staff concurrency and premium emoji; enable verified Drone deployment

src/core/health.py

@@ -0,0 +1,30 @@
+"""Health reflects a live event loop and a usable database connection."""
+import asyncio
+import os
+import time
+from pathlib import Path
+
+from sqlalchemy import text
+
+from .database import async_session_maker
+
+HEARTBEAT = Path(os.getenv("HEARTBEAT_FILE", "/tmp/lottery-heartbeat"))
+
+
+async def heartbeat():
+    while True:
+        async with async_session_maker() as session:
+            await session.execute(text("SELECT 1"))
+        HEARTBEAT.write_text(str(time.time()), encoding="ascii")
+        await asyncio.sleep(10)
+
+
+def healthy():
+    try:
+        return 0 <= time.time() - float(HEARTBEAT.read_text(encoding="ascii")) < 60
+    except (OSError, ValueError):
+        return False
+
+
+if __name__ == "__main__":
+    raise SystemExit(0 if healthy() else 1)