[codex] test(error-boundary): cover fallback and recovery

[prettyboyvic]

Summary

• add component tests for fallback rendering, light/dark themes, guarded logging, reset recovery, home navigation, and production-safe error details
• route caught errors through the shared logger instead of raw console.error
• reset the boundary without forcing a full page reload
• keep dependency tests excluded from Vitest collection

Security notes

• production fallback UI does not expose error messages or stack context
• caught errors are reported through the guarded application logger
• recovery clears only boundary state and re-renders the current child tree

Validation

• targeted ErrorBoundary tests — 6 passed
• targeted coverage — 100% statements, branches, functions, and lines
• full suite — 16 files / 198 tests passed
• Prettier check — passed
• ESLint — 0 errors; one existing Fast Refresh warning on the class-component export shape
• git diff --check — passed

Closes #38