fix(app): add worktree selector for git worktrees

[swalker326]

Issue for this PR

Closes #13782

Related: #14082, #10665

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

It fixes git worktree behavior in the sidebar by keeping one project entry but making the active worktree explicit and switchable in the project details area. Instead of rendering all worktrees as a long list, the sidebar now shows sessions for only the selected worktree and updates routing/session loading accordingly.

How did you verify your code works?

• Ran bun run typecheck in packages/app
• Ran bun test --preload ./happydom.ts in packages/app (228 pass)
• Manually verified switching between root repo and linked worktrees in the serve UI

Screenshots / recordings

UI change verified locally; can add screenshots if maintainers request.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Based on my search, I found a potentially related PR:

Related PR:

• feat(tui): add worktree support for session creation #13528 - feat(tui): add worktree support for session creation
  • feat(tui): add worktree support for session creation #13528
  • This appears to be related as it also adds worktree support, though it's for the TUI rather than the app UI. Worth checking if there's overlapping functionality or logic.

The other results (#4817, #12008, #14266) address different aspects of worktree or git functionality but don't appear to be direct duplicates of the worktree selector fix in PR #14374.

[github-actions]

Thanks for updating your PR! It now meets our contributing guidelines. 👍