Add automatic retry logic to doRequest for HTTP 429 responses. Uses
Retry-After header when present, otherwise exponential backoff
(1s, 2s, 4s). Respects context cancellation during waits. Defaults
to 3 max retries with 1s base delay. Includes 7 new tests covering
retry success, exhaustion, Retry-After header, context cancellation,
non-429 errors, and backoff calculation.
Closesleeworks-agents/gitea-mobile#132
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>