fix(http2): reject upgrade streams closed before response headers

[trivikr]

This relates to...

Fixes: #5064

Rationale

The H2 upgrade paths only advanced the request once a response event arrived.

If the peer closed the stream before sending headers, the request was never settled and the queue slot was not released, which could leave the operation hanging and interfere with later cleanup.

Changes

• Added shared pre-response handling for H2 upgrade streams in lib/dispatcher/client-h2.js
• Count upgrade/connect streams as open immediately after session.request(...)
• Reject upgrade/connect requests on pre-header error, end, or close
• Advance the client queue when those failures happen so the request does not remain stuck

Features

N/A

Bug Fixes

• Fixed an H2 websocket upgrade hang when the server closes the stream before sending response headers
• Fixed the same pre-header hang in the H2 CONNECT path
• Fixed request queue cleanup for those failure cases so client.close() does not wait on a stuck upgrade/connect request

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

[mcollina]

CI is very red

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.24561% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 93.11%. Comparing base (79b7ebd) to head (6bc1a56).

Files with missing lines	Patch %	Lines
lib/dispatcher/client-h2.js	98.24%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5069      +/-   ##
==========================================
+ Coverage   93.09%   93.11%   +0.01%     
==========================================
  Files         110      110              
  Lines       35801    35818      +17     
==========================================
+ Hits        33330    33351      +21     
+ Misses       2471     2467       -4     

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[trivikr]

The CI failures caused by timeouts in ‎test/websocket/opening-handshake.js were fixed by tracking server-side HTTP/2 sessions and closing them explicitly during teardown

[mcollina]

lgtm

[mcollina]

lgtm