Add Token refresh #5
Description
Not sure if HA handles this automatically, otherwise:
The OAuth implementation is missing token refresh handling. When using OAuth authentication, access tokens typically expire and need to be refreshed. The current implementation in async_setup_entry directly accesses token.get("access_token") without handling token refresh. Consider using the OAuth2 session or implementation's token refresh mechanism to ensure tokens are automatically refreshed when expired.
Originally posted by @Copilot in #2 (comment)