fix: handle incomplete stack frames in error overview

[cyphercodes]

Summary

• Render stack-utils incomplete stack frames (for example at native) as raw stack lines instead of structured frames with undefined fields.
• Give repeated stack lines unique, stable keys so trailing/empty stack lines do not trigger React duplicate-key warnings.
• Add focused ErrorOverview regression coverage for native frames and repeated blank stack lines.

Closes #963

Test Plan

• FORCE_COLOR=true npx ava test/error-overview.tsx --serial
• FORCE_COLOR=true npx ava test/errors.tsx test/error-overview.tsx --serial
• npm run typecheck
• npm run lint (passes with existing warnings in unrelated files)
• npm run build
• git diff --check

Note: I also ran npm test; it reached the broad AVA suite but failed in unrelated existing tests (alternate-screen-example, cursor, and measure-element) outside the touched ErrorOverview surface.

[sindresorhus]

This still misses named native frames. I manually checked parseLine(' at foo (native)'), and it returns {native: true, function: 'foo'}. Since function is present, the new guard takes the structured frame path even though there is no file, line, or column.

Rendering that stack line currently produces - foo (::), and the aria label includes line undefined column undefined.

I think the guard should treat frames without source location data as incomplete too, not just frames where both file and function are missing. Otherwise this fix covers at native, but not at foo (native).

[cyphercodes]

Updated this PR to handle named native frames like at foo (native) as incomplete stack frames too, so they render as the original raw stack line instead of foo (::) / undefined source-location metadata.

Local verification:

• npm run typecheck ✅
• npx xo src/components/ErrorOverview.tsx test/error-overview.tsx ✅
• FORCE_COLOR=true npx ava test/error-overview.tsx ✅
• git diff --check ✅