Remove the dead errorHandlingTest.ts file from src/utils

[nanaf6203-bit]

Remove the dead errorHandlingTest.ts file from src/utils

Labels / Complexity: Frontend · Trivial — Trivial

Summary

src/utils/errorHandlingTest.ts is a 'use client' file that exercises the error-handling system (logger, errorMonitoring, ErrorCategory, ErrorSeverity) but is never imported — a workspace grep for errorHandlingTest / testErrorHandling returns only the file itself and its own content. It ships in the production bundle ('use client'), adding dead code and confusion: a contributor reading src/utils/ sees a "Test file to verify the new error handling implementation" and reasonably assumes the system is exercised in CI, when nothing runs it.

Proposal

• Delete src/utils/errorHandlingTest.ts.
• If any of its assertions are valuable, move them into a real *.test.ts under src/utils/__tests__/.

Acceptance criteria

• src/utils/errorHandlingTest.ts is gone; no import of it remains.
• npm run build and npm test pass.

Getting started

Files: src/utils/errorHandlingTest.ts. Verify with npm run build and npm test. Pattern-match src/utils/__tests__/earlyErrorSuppression.test.ts for where real tests live.