fix(runner): prevent Retry-After duration overflow

[steipete]

Large numeric Hugging Face Retry-After values overflowed Go’s nanosecond duration. With Retry-After: 9223372037, the client retried immediately and exhausted all six attempts instead of waiting for the server cooldown or cancellation.

Parse unsigned seconds and saturate at Go’s maximum duration before multiplication. Preserve ordinary numeric and HTTP-date cooldowns, context cancellation, and fallback behavior for malformed headers, including oversized numbers followed by junk. This addresses an overflow defect without introducing the premature-retry policy proposed in #50.

Regression proof uses a real local HTTP server: main returns HTTP 429 immediately for the overflowing header; the fix makes exactly one request and exits at the caller’s deadline. Boundary tests cover zero, a normal one-hour cooldown, both sides of the duration limit, values beyond uint64, negative values, malformed values, and HTTP dates. The focused tests were observed failing before the fix and passing afterward. Full Go tests, vet, and docs generation are required on AWS Crabbox before merge, alongside independent Codex review through P2 and exact-head CI.

Final validation passed on Go 1.27.1/Linux: go test -count=1 ./..., go vet ./..., and make docs-site on AWS Crabbox. Independent review is clean through P2 for the final diff, including malformed oversized headers.

[clawsweeper]

🦞👀
ClawSweeper picked this up.

Pull request received. I will update this pull request when review starts.

ClawSweeper review in progress

ClawSweeper is reviewing this revision. This supersedes any previous blocked status.

View the workflow run.