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/api.py

@@ -0,0 +1,60 @@
+"""Thin async client for the West Wood Club (PerfectGym) API.
+
+Authentication is a long-lived bearer token supplied by the user (see
+``get-token.py`` in the repo root for how to obtain one). Only the
+``Authorization`` header is required by the backend.
+"""
+
+from __future__ import annotations
+
+import aiohttp
+
+from .const import BASE_URL
+
+
+class WestWoodApiError(Exception):
+    """A request to the API failed."""
+
+
+class WestWoodAuthError(WestWoodApiError):
+    """The token was rejected (expired or revoked)."""
+
+
+class WestWoodClient:
+    """Minimal client wrapping the endpoints the integration needs."""
+
+    def __init__(self, session: aiohttp.ClientSession, token: str) -> None:
+        self._session = session
+        self._token = token
+
+    async def _get(self, path: str, **params: str) -> list[dict]:
+        """GET a wrapped endpoint and return its ``data`` list."""
+        try:
+            async with self._session.get(
+                f'{BASE_URL}{path}',
+                params=params,
+                headers={
+                    'Authorization': f'bearer {self._token}',
+                    'Accept': 'application/json',
+                },
+            ) as resp:
+                if resp.status in (401, 403):
+                    raise WestWoodAuthError(f'token rejected (HTTP {resp.status})')
+                resp.raise_for_status()
+                payload = await resp.json()
+        except aiohttp.ClientError as err:
+            raise WestWoodApiError(str(err)) from err
+
+        if payload.get('errors'):
+            raise WestWoodApiError(str(payload['errors']))
+        return payload.get('data') or []
+
+    async def async_get_clubs(self) -> dict[int, str]:
+        """Return ``{club_id: name}`` for every club in the tenant."""
+        data = await self._get('/v1/Clubs/Clubs', timestamp='0')
+        return {club['id']: club['name'] for club in data}
+
+    async def async_get_member_counts(self) -> dict[int, int]:
+        """Return ``{club_id: live_member_count}``."""
+        data = await self._get('/v1/Clubs/WhoIsInCount')
+        return {row['clubId']: row['count'] for row in data}