Replace text inputs with dropdowns in setup wizard
Step 1: Repository Selection
- Fetch and display all user repositories in a dropdown
- Add sort options: recently updated, recently created, by name
- Show loading state while fetching repositories
- Show error state if fetch fails
- Display repository count
Step 2: Folder Selection
- Fetch all directories from selected repository
- Display folders in dropdown with emoji icons
- Default option: root directory (all markdown files)
- Show loading state while fetching folders
- Show helpful message if no folders found
Benefits:
- No typing errors - users select from actual repositories
- Better UX - see what actually exists
- Automatic validation - can only select real repos/folders