Add copilot instructions.

.github/copilot-instructions.md

@@ -0,0 +1,64 @@
+# Copilot Instructions for Wino-Mail Project
+
+## ViewModels Development Guidelines
+
+### Observable Properties
+- **ALWAYS** use `public partial` observable properties in ViewModels
+- **NEVER** use private fields with `[ObservableProperty]` attribute
+- **Correct Pattern:**
+  ```csharp
+  [ObservableProperty]
+  public partial string SearchQuery { get; set; } = string.Empty;
+  ```
+- **Incorrect Pattern:**
+  ```csharp
+  [ObservableProperty]
+  private string searchQuery = string.Empty;
+  ```
+
+### ViewModels Structure
+- All ViewModels should inherit from appropriate base classes (MailBaseViewModel, CoreBaseViewModel, etc.)
+- Use `[RelayCommand]` for command methods
+- Follow the existing dependency injection patterns
+- Use `IMailDialogService` for Mail-related dialogs, `IDialogServiceBase` for core dialogs
+
+### Strings and Localization
+- All strings should be added in English to en-US.json file and used via Translator class.
+- Avoid hardcoding strings in the codebase.
+- Use Translator.{TranslationKey} with property to retrieve string in view models.
+- Use Translator as well in the XAML files with x:Bind. Always use OneTime mode.
+
+### Dialog Services
+- Use `InfoBarMessage()` method for simple notifications
+- Use `ShowConfirmationDialogAsync()` for confirmation dialogs
+- Use `PickFilesAsync()` for file selection
+- Always check for null/empty results from dialog operations
+
+### File Structure
+- Place ViewModels in appropriate projects (Wino.Mail.ViewModels, Wino.Core.ViewModels, etc.)
+- Create abstract page classes in Views/Abstract folders
+- Follow the existing naming conventions
+
+### Error Handling
+- Always wrap async operations in try-catch blocks
+- Use InfoBar messages for user-friendly error notifications
+- Log errors appropriately but don't expose technical details to users
+
+### Collection Management
+- Use ObservableCollection for UI-bound collections
+- Implement proper filtering and search functionality
+- Use virtualization for large datasets (ListView, ItemsView)
+
+### Contact Management Specific
+- Respect IsRootContact property - root contacts cannot be deleted
+- Check IsOverridden property during synchronization
+- Always validate contact data before operations
+- Use PersonPicture controls for contact avatars
+- Support multiple selection where appropriate
+
+## Code Style
+- Use var where type is obvious
+- Use string interpolation over string.Format where simple
+- Keep methods focused and single-responsibility
+- Use meaningful variable names
+- Add XML documentation for public APIs

WinoMail.slnx

@@ -6,6 +6,7 @@
   </Configurations>
   <Folder Name="/Solution Items/" Id="8ec462fd-d22e-90a8-e5ce-7e832ba40c5d">
     <File Path=".editorconfig" />
+    <File Path=".github/copilot-instructions.md" />
     <File Path="Directory.Build.Props" />
     <File Path="Directory.Packages.props" />
     <File Path="nuget.config" />