Add folder customization page for per-account folder management

[bkaankose]

To address #853, this PR brings a new page where users are given more power to re-order their folder layout as they wanted. Default is always alphabetic with respecting the system folder/pinned order.

Summary

Adds a new Folder Customization page that allows users to reorder, pin/unpin, and hide folders on a per-account basis. This feature provides granular control over folder visibility and organization in the navigation menu.

Key Changes

• New ViewModel: FolderCustomizationPageViewModel manages folder organization with three sections:

  • Pinned folders (sticky items)
  • Category folders (Gmail-specific virtual group)
  • More folders (remaining folders)

• New UI Page: FolderCustomizationPage with drag-and-drop reordering support via ListView.CanReorderItems, expandable sections for each folder group, and toggle buttons for pin/hide actions

• New Data Model: FolderCustomizationItemViewModel wraps MailItemFolder entities and exposes observable IsHidden property for UI binding

• Database Schema: Added Order column to MailItemFolder table to persist user-defined folder ordering (0 = no custom order)

• Service Layer Enhancements (IFolderService):

  • ChangeFolderHiddenStatusAsync() - Toggle folder visibility
  • UpdateFolderOrdersAsync() - Persist custom folder ordering
  • ResetFolderCustomizationAsync() - Restore default layout and visibility

• Folder Sorting Logic: Implemented ApplyFolderSort() method that orders folders by:

  1. Custom order (user-customized entries first)
  2. Alphabetic folder name (culture-aware)
  3. SpecialFolderType (canonical tiebreak)

• Navigation Integration:

  • Added FolderCustomizationPage to WinoPage enum
  • Added entry point in AccountDetailsPage with "Customize folder list" settings card
  • Registered view model and page in dependency injection

• Localization: Added 17 new translation keys for UI strings (title, descriptions, section headers, button tooltips, reset confirmation)

Notable Implementation Details

• Gmail accounts show a special "Categories" section for category-type folders (Promotions, Social, Updates, Forums, Personal) that cannot be individually pinned
• Folder customization is persisted per account and survives sync operations
• Reset functionality restores system folder stickiness and clears all custom ordering/hiding
• Drag-drop reordering automatically triggers PersistLayoutAsync() to save changes
• Existing folder customization is preserved during account sync (Order and IsHidden columns are retained)

https://claude.ai/code/session_01B1uTYYpQkWu137bqZo521n