feat: add system health diagnostics

backend/app/system_health/adapters.py

@@ -0,0 +1,29 @@
+"""External service adapters for System Health."""
+
+from collections.abc import Callable
+
+import redis
+
+from app.config import settings
+
+
+RedisFactory = Callable[[], redis.Redis]
+
+
+def default_redis_factory() -> redis.Redis:
+    return redis.Redis.from_url(
+        settings.redis_url,
+        socket_connect_timeout=2,
+        socket_timeout=2,
+    )
+
+
+class RedisHealthAdapter:
+    def __init__(self, factory: RedisFactory | None = None):
+        self._factory = factory or default_redis_factory
+
+    def ping(self) -> bool:
+        try:
+            return bool(self._factory().ping())
+        except Exception:
+            return False