Rate-limit handling crossed the climate→app boundary as prose: climate
raised RuntimeError(cooldown text), and app._weather_fetch_error re-parsed
it by keyword ('429'/'rate-limited'/'daily'/'tomorrow') while also calling
climate's private _is_rate_limit/_rate_limit_reason — and the user-facing
daily-quota copy existed verbatim in both modules.
climate now raises WeatherUnavailable (a RuntimeError subclass carrying
the user-facing text and a daily flag): from _load_history when both
sources fail with no stale cache, and from the forecast fetch on a 429.
limit_message() is the single home of the rate-limit copy; is_rate_limit
is public for the one remaining raw-429 fallback. app maps the typed
error to 503 by isinstance — no message parsing, no private imports.
The burst-limit copy is unified on 'The weather service is rate-limited…'
(the archive path previously said 'weather archive' internally but the
API always rewrote it; user-visible text is unchanged).
Tests: daily-quota 503 carries the 'tomorrow' copy, an unclassified raw
429 still maps to a clean 503, and a genuine fault stays a 502 with the
raw error.