chore: remove unused tab bar

[janburzinski]

Description

• remove unused legacy tab bar
• is still in features/tabs

Checklist

• I kept this PR small and focused
• I ran a self-review before opening this PR
• I ran the relevant local checks or explained why not
• I updated docs when behavior or setup changed
• I added or updated tests when behavior changed, or explained why not
• I only added comments where the logic is not obvious
• I used Conventional Commits for commit
  messages and, when possible, the PR title

[greptile-apps]

Greptile Summary

This PR removes the old shared tab bar code. The main changes are:

• Deleted the legacy ReorderList renderer helper.
• Deleted the legacy shared TabBar component.
• Left tab UI usage on the feature-local tabs implementation.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The deleted modules have no remaining callers in the inspected build scope.

Important Files Changed

Filename	Overview
apps/emdash-desktop/src/renderer/lib/components/reorder-list.tsx	Deleted the legacy generic Motion reorder-list helper.
apps/emdash-desktop/src/renderer/lib/ui/tab-bar.tsx	Deleted the legacy shared tab bar component and props type.

_{Reviews (1): Last reviewed commit: "chore(tabs): remove unused tab bar" | Re-trigger Greptile}