fix(bundle): preserve root output path

[Lexiie]

Summary

Resubmission of #205 after the release-process hiccup closed it without merge.

resolveBundleDir('/') currently strips the trailing slash before checking whether the path is absolute. For the filesystem root path, that turns / into an empty string, so the helper resolves it against process.cwd() instead of preserving /.

This PR keeps the root path intact while preserving the existing behavior for ordinary trailing slashes like /tmp/bundle/.

Changes

• Only strip a trailing slash when the raw path has more than one character.
• Add regression coverage that resolveBundleDir('/') returns /.

Verification

• rtk vitest run src/lib/bundle.test.ts -t "root|resolveBundleDir"
• rtk npx eslint src/lib/bundle.ts src/lib/bundle.test.ts --fix-dry-run --format stylish
• rtk npx eslint src/lib/bundle.ts src/lib/bundle.test.ts
• rtk npm run typecheck

Summary by CodeRabbit

• Bug Fixes
  • Preserved the filesystem root path when cleaning up output directories, so / is no longer reduced to an empty value.
  • Improved handling of paths with trailing slashes, keeping valid root paths intact while still normalizing other paths.
  • Added coverage for the root-path case to prevent regressions.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 3305dfa and 40cf454.

📒 Files selected for processing (2)

• src/lib/bundle.test.ts
• src/lib/bundle.ts

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Walkthrough

The resolveBundleDir function in src/lib/bundle.ts now only trims a trailing / when the resulting path would remain non-empty, preventing the root path / from being reduced to an empty string. A corresponding test case was added to verify this behavior.

Changes

resolveBundleDir root path fix

Layer / File(s)	Summary
Preserve root path in trailing-slash trimming src/lib/bundle.ts, src/lib/bundle.test.ts	resolveBundleDir now trims a trailing / only when the path length exceeds 1 character, preserving '/' as-is; a new test verifies resolveBundleDir('/') returns '/'.

Estimated code review effort: 1 (Trivial) | ~3 minutes

Suggested reviewers: ruili-testsprite, zeshi-du

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the main change: preserving the root bundle output path instead of stripping it.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[zeshi-du]

The bug this patched was real, but the surrounding code was structurally rewritten by the Windows-support work that landed on main — resolveBundleDir now routes through a stripTrailingSeparators helper that already preserves the root path ('/' and 'C:' both return unchanged), which is why this branch shows as conflicting with nothing left to patch. Closing as already-fixed. If you'd like the credit for the gap you spotted: main has no explicit POSIX-root regression test — a one-line test PR asserting resolveBundleDir('/') === '/' against current main would be welcome. Thanks @Lexiie!