fix: preserve SDK errors for invalid JSON byte encodings

[Bortlesboat]

Malformed JSON bytes now raise the usual SDK error with the response status and headers in both sync and async requests. For example, a 429 response containing invalid UTF-8 previously leaked UnicodeDecodeError, bypassing the SDK error contract and its Retry-After metadata.

Validation: the new encoding cases produced 12 failures before the fix; all 646 tests now pass with python -m pytest --cov=resend --cov-report=xml --doctest-modules tests. The tests cover invalid UTF-8, truncated UTF-16 and malformed JSON at HTTP 200, 429 and 502 through both transport adapters. Source flake8 passes on Python 3.11, and mypy passes across resend/, examples/ and tests/ on Python 3.12.

No service deployment or new monitoring is needed for this SDK error conversion.

Agent-assisted: Codex prepared the patch and ran the local checks listed above.

---

---

Summary by cubic

Fixes sync and async request decoding so malformed byte encodings in JSON responses raise the SDK's standard error with response status and headers instead of leaking UnicodeDecodeError.

• Adds UnicodeDecodeError to the JSON decode except clause in resend/request.py and resend/async_request.py.
• Adds tests for invalid UTF-8, truncated UTF-16, and malformed JSON at HTTP 200, 429, and 502 through both sync and async adapters.
• Bumps version to 2.43.1.

^{Written for commit d9fa06e. Summary will update on new commits.}

[gabrielmfern]

thanks

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.90%. Comparing base (7f1acd0) to head (eba77a8).
⚠️ Report is 226 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff             @@
##             main     #276       +/-   ##
===========================================
+ Coverage   82.66%   96.90%   +14.24%     
===========================================
  Files           4       72       +68     
  Lines          75     4076     +4001     
===========================================
+ Hits           62     3950     +3888     
- Misses         13      126      +113     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Bortlesboat]

Fixed the mypy failure in d9fa06e. The new response-decoding test now runs its coroutine with asyncio.run, avoiding the untyped pytest decorator while retaining the async request and status/header assertions. Preserved the intervening version bump. All 646 tests pass, mypy passes across 181 source files, and Flake8 passes.