fix(websocket): use 1002 close code on parser errors

[deepview-autofix]

onParserError passed null as the close code to failWebsocketConnection, causing closeWebSocketConnection to default the code to 1000 ("Normal Closure") whenever the reason string was non-empty. Protocol errors (invalid frames, RSV bit violations, etc.) surfaced through the parser were thus reported to the peer as normal closures instead of 1002 ("Protocol Error"), violating RFC 6455 section 7.4.1.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.03%. Comparing base (d2e8178) to head (664aebe).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5051   +/-   ##
=======================================
  Coverage   93.03%   93.03%           
=======================================
  Files         110      110           
  Lines       35793    35793           
=======================================
+ Hits        33299    33300    +1     
+ Misses       2494     2493    -1     

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[KhafraDev]

Instead of a simulated error, could we test for one of the following?

Protocol errors (invalid frames, RSV bit violations, etc.)