- Retry CDN requests only for transient errors and honor Retry-After
(Cloudflare error 1200 sends 60 s), with jitter.
- Read helper and Sentinel versions from the local versions.json, which
the hourly update check refreshes, instead of fetching per job/server.
- Replace the random 0-600 s delay with a stable per-instance offset
inside the cron interval (max 1 h).
- Manual update checks and upgrades make one CDN attempt only.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
