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/package.json

@@ -49,8 +49,11 @@
     "@radix-ui/react-dropdown-menu": "^2.1.16",
     "@radix-ui/react-label": "^2.1.8",
     "@radix-ui/react-popover": "^1.1.15",
+    "@radix-ui/react-radio-group": "^1.3.8",
+    "@radix-ui/react-select": "^2.2.6",
     "@radix-ui/react-slider": "^1.3.6",
     "@radix-ui/react-slot": "^1.2.4",
+    "@radix-ui/react-switch": "^1.2.6",
     "@radix-ui/react-tabs": "^1.1.13",
     "@radix-ui/react-tooltip": "^1.2.8",
     "@tanstack/react-query": "^5.90.12",