client: cache llhttp wasm buffer view

[trivikr]

This relates to...

N/A

Rationale

Parser#execute() copied every socket chunk into wasm memory through a newly created Uint8Array view.
The wasm buffer allocation is already reused until a larger chunk arrives, so the memory view can be cached too.

Changes

Cache the llhttp wasm memory view alongside currentBufferPtr and currentBufferSize, refreshing it only when needed.

Features

N/A

Bug Fixes

N/A

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

Assisted-by: openai:gpt-5.5

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.14%. Comparing base (5c96f7d) to head (27e470c).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5115   +/-   ##
=======================================
  Coverage   93.14%   93.14%           
=======================================
  Files         110      110           
  Lines       35898    35908   +10     
=======================================
+ Hits        33436    33446   +10     
  Misses       2462     2462           

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[mcollina]

lgtm