The tooltip only checked paused/authenticated/idle/running states.
When Spotify was rate limited or daily budget exhausted, the worker
thread was still alive (sleeping in guards) so it showed "Running"
with no current item and stale 0% progress.
Now checks rate_limited and daily_budget.exhausted before running:
- Rate limited: "Rate Limited — Waiting Xm for rate limit to clear"
- Budget exhausted: "Daily Limit Reached — Resets in Xh Xm"
- No current item: "Waiting for next item..." instead of blank
Also adds rate_limit info object to get_stats() response for the
countdown display.
7133595e0d
