fix(retry): make RetryController rawHeaders/rawTrailers writable

[pacocartones]

Fixes #5726.

Problem

RetryController (lib/handler/retry-handler.js) exposed rawHeaders and rawTrailers as getter-only accessors, but the real RequestController (lib/core/request.js) declares them as writable data properties. Interceptors composed downstream of retry legitimately reassign them — the decompress interceptor does controller.rawHeaders = filteredHeaders (to strip content-encoding/content-length), and the cache interceptor does the same. When retry sits ahead of decompress, the interceptor gets the retry proxy and the assignment throws:

TypeError: Cannot set property rawHeaders of #<RetryController> which has only a getter

rawTrailers had the identical latent defect (assigned by request.js and mock-utils.js).

Fix

Add forwarding setters to the proxy, mirroring the existing getters and the writable fields of the real controller — making the proxy transparent for writes as it already is for reads. Consistent with the proxy's design ("always forwards to the controller of the currently active connection").

Test

• test/retry-handler-controller-proxy.js — unit: forwards rawHeaders/rawTrailers writes (RED: getter-only TypeError; GREEN: forwarded).
• test/interceptors/decompress.js — end-to-end: retry composed before decompress (RED at HEAD; GREEN with fix).

decompress 28/28, retry-handler/retry-agent suites, npm run lint — all green.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.50%. Comparing base (17117f6) to head (14f8c3d).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5766      +/-   ##
==========================================
- Coverage   93.50%   93.50%   -0.01%     
==========================================
  Files         110      110              
  Lines       39072    39074       +2     
==========================================
+ Hits        36534    36535       +1     
- Misses       2538     2539       +1     

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[mcollina]

Sorry, can you rebase?

[pacocartones]

Closing this — it turned out to duplicate #5727 (by @official-burak), which landed the same rawHeaders/rawTrailers setters on RetryController plus equivalent regression tests, and has already merged into main. So there's nothing left for this PR to add and no rebase is needed. Thanks @mcollina for taking a look! 🙏