fix(websocket): avoid double-closing canceled stream readers

[colinaaa]

This relates to...

Closes #5103
Closes #5104

Rationale

WebSocketStream could throw ERR_INVALID_STATE when readable.cancel() closed the internal controller before the later clean-close path tried to close it again. This keeps the readable shutdown path idempotent and prevents the uncaught exception.

Changes

• reuse readableStreamClose() in the clean WebSocketStream socket close path instead of calling ReadableStreamDefaultController.close() directly
• add a regression test that cancels the readable stream before a clean close handshake and asserts no uncaught exception escapes

Features

N/A

Bug Fixes

• fix a WebSocketStream double-close path that could throw TypeError [ERR_INVALID_STATE]: Invalid state: Controller is already closed
• cover the cancel-then-clean-close sequence with a websocket stream regression test

Breaking Changes and Deprecations

N/A

Status

• I have read and agreed to the Developer's Certificate of Origin
• Tested
• Benchmarked (optional)
• Documented
• Review ready
• In review
• Merge ready

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.15%. Comparing base (67ca48c) to head (d9b7fef).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5105      +/-   ##
==========================================
+ Coverage   93.13%   93.15%   +0.01%     
==========================================
  Files         110      110              
  Lines       35826    35826              
==========================================
+ Hits        33368    33375       +7     
+ Misses       2458     2451       -7     

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