feat: auto retry rate limit

[FreekBes]

Added retry logic that automatically requeues requests when they return a 429 or 5xx error.

• 429 (rate limit): retried indefinitely, waiting for the duration of the Retry-After header (or retryAfterFallback seconds when it is absent). Applies to every request, including writes — a 429 is rejected before processing, so it is always safe to retry.
• 5xx (server error): retried up to maxServerErrorRetries times (default 5), waiting serverErrorBackoff ms between attempts. Only GET requests are retried on 5xx, since writes (post/put/patch/delete) may not be idempotent. After the retries are exhausted the last Response is returned, so existing .ok/.status checks keep working.

Added more config for this:

interface RetryConfig {
    enabled?: boolean; // master switch, default is true
    maxServerErrorRetries?: number; // max retries on 5xx errors per request, default is 5. 429s are always retried indefinitely.
    serverErrorBackoff?: number; // base ms to wait before retrying a 5xx error, default is 30000
    retryAfterFallback?: number; // seconds to wait on a 429 when no Retry-After header is present, default is 1
    jitter?: number; // max random extra ms added to every retry wait, default is 10000
}

[Copilot]

Pull request overview

Adds automatic retry behavior to Fast42 API requests, integrating rate-limit (429) and server-error (5xx) retries into the internal request scheduling so callers can keep using the existing Response contract.

Changes:

• Introduces retry configuration (RetryConfig) with defaults and a master enable/disable switch.
• Wraps internal request scheduling with scheduleWithRetry to transparently retry 429s (indefinitely) and GET 5xx responses (bounded).
• Adds Jest coverage for the retry behavior and documents configuration/behavior in the README.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
src/index.ts	Adds retry config defaults and implements scheduleWithRetry used by GET and write requests.
tests/index.test.ts	Adds unit tests validating 429 and 5xx retry behavior and default retry settings.
README.md	Documents the new retry feature and configuration and removes now-unneeded manual 429 retry example logic.

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[github-actions]

🎉 This PR is included in version 3.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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