X_SOURCE_BARE_ERROR

shipped source throws a bare builtin Error

CLAUDE.md says never throw a bare Error, and the check that read it (checkErrorFixes) skips tests — so the half that ships had no guard at all. Two bare throws sat in @ultimat3/ai's two wire readers, where a SyntaxError was thrown and caught by the very catch that re-threw it as a coded transport error. A fixture double that throws AT the subject is shipped source too, and no shape tells the two apart: scripts/lib/source-bare-error-exemptions.ts names every intentional site, one row per site, and this is every other one

replace the throw with a coded error — new UltimateError({ code, cause, fix }) from @ultimat3/core, or new ScriptError({ code, cause, fix }) from scripts/lib/script-error.ts in a script — or add the site to scripts/lib/source-bare-error-exemptions.ts with the reason it is allowed