doorbell-listener: add PEP 723 inline deps for uv auto-resolve

uv run without a project file (pyproject.toml/requirements.txt) won't
auto-resolve from script imports — needs inline metadata per PEP 723.

Fix: add # /// script block declaring requests + paho-mqtt>=2.0.

infra/doorbell-listener/doorbell-listener.py

@@ -1,4 +1,11 @@
 #!/usr/bin/env python3
+# /// script
+# requires-python = ">=3.10"
+# dependencies = [
+#     "requests",
+#     "paho-mqtt>=2.0",
+# ]
+# ///
 """Doorbell ntfy listener.
 
 Polls one or more ntfy topics and toggles a smart plug via zigbee2mqtt every