Handle rate limit headers in client, adjust request throttling

[piceri]

This request:

• Adjusts client to respect rate limit headers from the GitHub API
  • Retry-After and X-Ratelimit-Reset headers are both checked, largest delay is applied
  • Rate limit delays are shared by all workers
• Renamed existing rateLimiter to requestThrottler and lowered throughput to 180 requests/min
• Add User-Agent to client request to quickly distinguish Deployment Tracker requests,

[Copilot]

Pull request overview

Updates the deployment record client to better handle GitHub API rate limiting by deriving a shared backoff from response headers and applying a renamed/request throttling mechanism across workers.

Changes:

• Add shared, cross-goroutine rate-limit backoff based on Retry-After and X-Ratelimit-Reset headers.
• Rename rateLimiter to requestThrottler and adjust the default throughput configuration.
• Add User-Agent header and extend tests to cover rate-limit delay parsing and cross-goroutine behavior.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

File	Description
pkg/deploymentrecord/client.go	Implements server-driven backoff using rate-limit headers, renames/throttles request limiter, and adds a User-Agent.
pkg/deploymentrecord/client_test.go	Updates existing rate-limit tests and adds new unit/concurrency tests for rate-limit delay parsing and shared backoff behavior.

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[ajbeattie]

LGTM, with a +1 on the Copilot comment about either removing the max 60 second Retry After or adding a note explaining it.

[piceri]

LGTM, with a +1 on the Copilot comment about either removing the max 60 second Retry After or adding a note explaining it.

Thanks! Removed the check, secondary rate limits should reset every min but it should be good enough to trust the header value.