Merge main into refactor/frontend

Merge latest features from main including:
- PR #161 (worktree-confusion): Clarified branch handling in dialogs
- PR #160 (speckits-rebase): Planning mode functionality

Resolved conflicts:
- add-feature-dialog.tsx: Combined TanStack Router navigation with branch selection state
- worktree-integration.spec.ts: Updated tests for new worktree behavior (created at execution time)
- package-lock.json: Regenerated after merge

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

apps/ui/src/components/views/board-view/shared/index.ts

@@ -4,3 +4,5 @@ export * from "./thinking-level-selector";
 export * from "./profile-quick-select";
 export * from "./testing-tab-content";
 export * from "./priority-selector";
+export * from "./branch-selector";
+export * from "./planning-mode-selector";