feat: add profile includes management UI

- Add includes section to profile editor with drag-and-drop reordering
- Display included profiles with scope badges (Global, Project, Tool)
- Add 'Add Include' dropdown filtered by compatibility and cycle prevention
- Add remove button per include row
- Save includes together with profile form
- Add include count badges to profile list sidebar
- Add drag icon to Icon component

Implements config-profile-includes-ui tasks 1.1-4.3

openspec/changes/config-profile-includes-ui/tasks.md

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+## 1. Core Includes UI
+
+- [x] 1.1 Add includes section to profile editor form with heading and empty state
+- [x] 1.2 Display current includes list with profile names and scope badges
+- [x] 1.3 Add remove button per include row
+- [x] 1.4 Add "Add Include" dropdown with available profiles filtered by validity
+- [x] 1.5 Implement frontend cycle detection to filter dropdown options
+- [x] 1.6 Save includes together with profile form on save
+
+## 2. Drag and Drop Reordering
+
+- [x] 2.1 Add drag-and-drop reordering to includes list using native HTML5 DnD
+- [x] 2.2 Update order indices after drag-and-drop reorder
+- [x] 2.3 Add visual feedback during drag (ghost image, drop target highlight)
+
+## 3. Profile List Enhancements
+
+- [x] 3.1 Add include count badge to profile list items
+
+## 4. Polish and Error Handling
+
+- [x] 4.1 Handle API cycle errors gracefully with user-friendly messages
+- [x] 4.2 Ensure save rollback on partial failure (profile saved but includes failed)
+- [x] 4.3 Add loading states for includes operations
+
+## 5. Quality Gates
+
+- [x] 5.1 TypeScript type check passes
+- [ ] 5.2 Manual testing: add, remove, reorder includes
+- [ ] 5.3 Manual testing: cycle prevention in UI
+- [ ] 5.4 Manual testing: save includes with profile form