Round out the built-in exceptions against the Feathers errors API: add
named classes for every common status (400/402/405/406/408/409/411/429/
500/501/502/503), each with a fixed status and stable machine code, plus
STATUS_TEXT labels for the new statuses.

Add an optional `data` bag to HttpException that surfaces in the JSON body,
and a toJSON() returning the rendered body shape (overridden by
ValidationException to include `errors`). Wire `data` into the kernel.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Tn7UJG3uSLwPcWaKo9gHgC