Adds CONF_BASE_URL/DEFAULT_BASE_URL and threads base_url through every
AsyncOpenAI construction site: config_flow.validate_input,
__init__.async_setup_entry, and config_flow's web-search geolocation
helper (_get_location_data) — the easy one to miss, since it would
otherwise silently talk to api.openai.com when the user configured a
different endpoint.
Fixes upstream-ported fixtures (conftest.mock_config_entry,
test_config_flow's inline MockConfigEntry/data-schema assertions) to
supply base_url now that the config-flow schema requires it.
No translations/en.json exists in this repo (only strings.json), so
only strings.json got the new "base_url" UI strings.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01739Seac5eMAfNwFeiwV5r4
