Add Home Assistant integration

Token-authenticated custom component exposing live per-club member counts
as sensors under a single "West Wood Club" device, fed by one coordinator
polling `/v1/Clubs/WhoIsInCount`.

Packaged via `buildHomeAssistantComponent` with a flake package + overlay so
it can be used in `services.home-assistant.customComponents`.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

custom_components/west_wood_club/const.py

@@ -0,0 +1,15 @@
+"""Constants for the West Wood Club integration."""
+
+from datetime import timedelta
+
+DOMAIN = 'west_wood_club'
+
+# PerfectGym Go backend (West Wood is a white-label tenant).
+BASE_URL = 'https://goapi2.perfectgym.com'
+
+# Config entry keys.
+CONF_TOKEN = 'token'
+CONF_CLUBS = 'clubs'
+
+# How often to poll live occupancy.
+UPDATE_INTERVAL = timedelta(minutes=5)