Add error handler for RateLimit error

[NerdyBoyCool]

ref: #31
ref: https://resend.com/docs/api-reference/rate-limit

Thank you for developing Ruby SDK.

Summary

When calling the Resend API from Ruby/Rails applications, we need to properly handle rate limit errors. Currently, RateLimitExceededError doesn't provide information.

This PR enhances rate limit error handling by adding detailed rate limit information to RateLimitExceededError.

Changes

• Enhanced RateLimitExceededError class: Added attributes to expose rate limit metadata:
  • rate_limit_limit: Maximum number of requests allowed
  • rate_limit_remaining: Number of requests remaining in current window
  • rate_limit_reset: Timestamp when the rate limit resets
  • retry_after: Number of seconds to wait before retrying
• Updated error initialization: Modified Resend::Error base class to accept and store response headers,
  enabling errors to access rate limit information from API responses
• Simplified error handling: Refactored handle_error! method in lib/resend/request.rb to streamline error
  instantiation with headers
• Added comprehensive tests: Updated specs to verify that RateLimitExceededError correctly parses and exposes
  rate limit headers

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Summary by cubic

Add detailed rate limit data to RateLimitExceededError and propagate response headers when raising errors. Apps can now read limit, remaining, reset, and retry-after to implement proper backoff.

• New Features
  • Expose rate_limit_limit, rate_limit_remaining, rate_limit_reset, retry_after on RateLimitExceededError.
  • Store response headers on Resend::Error; handle_error! now passes headers to all errors.
  • Updated specs to verify header parsing and exposed attributes.

[NerdyBoyCool]

@drish
Hello. Colud you review this PR?

[cubic-dev-ai]

2 issues found across 3 files

Prompt for AI agents (all 2 issues)

Understand the root cause of the following 2 issues and fix them.


<file name="lib/resend/errors.rb">

<violation number="1" location="lib/resend/errors.rb:24">
RateLimitExceededError needs to pass the headers up to Error#initialize so error.headers exposes the actual response headers.</violation>
</file>

<file name="lib/resend/request.rb">

<violation number="1" location="lib/resend/request.rb:50">
`resp[:headers]` reads the parsed JSON body, not the HTTP headers exposed by HTTParty, so the rate limit metadata will always be empty. Please pull the headers from `resp.headers` instead so RateLimitExceededError receives the real values.</violation>
</file>

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[drish]

this is great @NerdyBoyCool , thank you for your contribution !

[NerdyBoyCool]

@drish
Thank you for the quick review! 🙇

I'll leave the timing of releases and merges to the repository owner！

[drish]

@drish Thank you for the quick review! 🙇

I'll leave the timing of releases and merges to the repository owner！

ill merge this and have a release going soon