test(worktree): fix macOS path baseline

[catwithtudou]

Summary

• Canonicalize the git-worktree test temp root with realpathSync so macOS /var and /private/var paths compare consistently with git's worktree output.
• Add a small retry window to the test temp-dir cleanup, which makes real-git worktree cleanup less flaky on macOS after path canonicalization.

Validation

• CI=true npx --yes pnpm@9.5.0 vitest run --project unit test/git-worktree.test.ts
• CI=true npx --yes pnpm@9.5.0 build
• CI=true npx --yes pnpm@9.5.0 test no longer reports test/git-worktree.test.ts failures. The remaining failures are out of scope for this PR: the group/status baseline covered by test(groups): fix group creation unit baseline #318, plus the existing test/sandbox.test.ts opaque-dir case.