feat: Everything2Everything 양방향 변환 매트릭스 피보팅

EverythingToJpeg(N→JPEG 단방향)에서 Everything2Everything(N×M 매트릭스)으로
앱을 피보팅. 7개 Provider, 200+ 변환 쌍 지원.

리네이밍
- 디렉토리/솔루션/csproj/namespace/AssemblyName/MSIX Identity 일괄 치환
- 임시파일 prefix e2j_ → e2e_, 로고 라벨 E2J → E2E

아키텍처
- ConversionPair(input, output) 신규 + ProviderCapability.SupportedConversions
- IConverterProvider.ConvertAsync에 outputExtension 파라미터 추가
- ProviderRegistry를 Dictionary<(input, output), Provider> 매트릭스로 재작성
  + OutputsForInput / OutputsForFile 쿼리 API
- ConversionEngine: 출력 ext 라우팅, 동일 입출력 자동 skip,
  서브폴더 suffix를 출력 ext에서 자동 도출
- ConvertOptions를 형식별 sub-record로 분리
  (Jpeg/Png/Webp/Avif/Tiff/Pdf*/Html*/Ocr)

Provider 매트릭스
- MagickProvider: PNG/JPEG/WebP/AVIF/BMP/TIFF/GIF/PDF 양방향 + RAW/PSD 디코딩
  (단일이미지→1페이지 PDF, GIF/TIFF→다페이지 PDF)
- HeicProvider: HEIC/HEIF → 이미지 7종
- PdfProvider: PDF → 이미지 6종 (PNG임베드 후 ImageMagick 인코딩)
- HtmlProvider: HTML/HTM → 이미지 + PDF (CDP printToPDF)
- DocxProvider/HwpxProvider: PDF + 이미지 7종 (LibreOffice 활용)
- OcrProvider 신규: 이미지/PDF → TXT/DOCX
  (Windows.Media.Ocr + DocumentFormat.OpenXml, PDF는 페이지별 OCR 후 결합)

UI
- 사이드바 TARGET FORMAT을 동적 ComboBox로 (큐 파일 매트릭스의 교집합만 표시)
- 출력 형식별 색상 배지 + Quality 패널 라벨 동적
- OUTPUT DESTINATION hint도 출력 ext 기반 동적

CLI
- 신규 'to <ext> <files...>' verb (예: to png photo.heic doc.docx)
- help 텍스트 양방향 컨셉으로 갱신

셸 통합
- ContextMenuRegistrar 카스케이드로 재설계
  (ExtendedSubCommandsKey + Everything2Everything.SubMenu.<ext>)
- 입력별 매트릭스에 따라 인기 출력 10종(JPEG/PNG/WebP/PDF/TXT/DOCX/AVIF/GIF/TIFF/BMP)
  동적 노출, 마지막에 '변환…' 옵션
- 메뉴 라벨 'JPEG로 변환' → 'Everything2Everything으로 변환'

기타
- Core.csproj TFM net9.0-windows → net9.0-windows10.0.19041.0 (WinRT API용)
- DocumentFormat.OpenXml 3.1.0 NuGet 추가
- README 양방향 매트릭스 기준 전면 개편
- MSIX appxmanifest Description / IExplorerCommand DLL 라벨 갱신

빌드: 0 errors, 0 warnings

src/Everything2Everything.App/Views/DiagnoseWindow.xaml.cs

@@ -0,0 +1,118 @@
+using System.Windows;
+using System.Windows.Controls;
+using System.Windows.Media;
+using Everything2Everything.Core;
+using Everything2Everything.Core.Providers;
+using Wpf.Ui.Controls;
+
+namespace Everything2Everything.App.Views;
+
+public partial class DiagnoseWindow : FluentWindow
+{
+    private readonly ConversionEngine _engine;
+
+    public DiagnoseWindow(ConversionEngine engine)
+    {
+        _engine = engine;
+        InitializeComponent();
+        Loaded += async (_, _) => await PopulateAsync();
+    }
+
+    private async Task PopulateAsync()
+    {
+        ItemsPanel.Children.Clear();
+
+        ItemsPanel.Children.Add(BuildSection("환경", new[]
+        {
+            ("OS", Environment.OSVersion.VersionString),
+            (".NET", Environment.Version.ToString()),
+            ("실행 경로", Environment.ProcessPath ?? AppContext.BaseDirectory),
+        }));
+
+        foreach (var provider in _engine.Providers.All)
+        {
+            var availability = await provider.CheckAvailabilityAsync();
+            ItemsPanel.Children.Add(BuildProviderCard(provider, availability));
+        }
+    }
+
+    private static UIElement BuildSection(string title, IEnumerable<(string Key, string Value)> items)
+    {
+        var card = new CardControl { Padding = new Thickness(16, 12, 16, 12), Margin = new Thickness(0, 0, 0, 12) };
+        var stack = new StackPanel();
+        stack.Children.Add(new TextBlock
+        {
+            Text = title,
+            FontSize = 14,
+            FontWeight = FontWeights.SemiBold,
+            Margin = new Thickness(0, 0, 0, 8),
+        });
+        foreach (var (k, v) in items)
+        {
+            var row = new Grid { Margin = new Thickness(0, 2, 0, 2) };
+            row.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(120) });
+            row.ColumnDefinitions.Add(new ColumnDefinition { Width = new GridLength(1, GridUnitType.Star) });
+            var keyText = new TextBlock { Text = k, FontSize = 12, Foreground = (Brush)Application.Current.FindResource("TextFillColorSecondaryBrush") };
+            var valueText = new TextBlock { Text = v, FontSize = 12, TextTrimming = TextTrimming.CharacterEllipsis };
+            Grid.SetColumn(valueText, 1);
+            row.Children.Add(keyText);
+            row.Children.Add(valueText);
+            stack.Children.Add(row);
+        }
+        card.Content = stack;
+        return card;
+    }
+
+    private UIElement BuildProviderCard(IConverterProvider provider, ProviderAvailability availability)
+    {
+        var card = new CardControl { Padding = new Thickness(16, 12, 16, 12), Margin = new Thickness(0, 0, 0, 12) };
+        var stack = new StackPanel();
+        var header = new StackPanel { Orientation = Orientation.Horizontal };
+        header.Children.Add(new TextBlock
+        {
+            Text = provider.Capability.DisplayName,
+            FontSize = 14,
+            FontWeight = FontWeights.SemiBold,
+        });
+        var (badgeText, brushKey) = (provider.Capability.Status, availability.IsReady) switch
+        {
+            (ProviderStatus.ComingSoon, _) => ("개발 중", "BadgeMutedBrush"),
+            (ProviderStatus.Disabled, _) => ("비활성", "BadgeMutedBrush"),
+            (_, true) => ("준비됨", "BadgeReadyBrush"),
+            _ => ("점검 필요", "BadgeWarnBrush"),
+        };
+        header.Children.Add(new Border
+        {
+            Background = (Brush)Application.Current.FindResource(brushKey),
+            CornerRadius = new CornerRadius(10),
+            Padding = new Thickness(8, 2, 8, 2),
+            Margin = new Thickness(8, 0, 0, 0),
+            Child = new TextBlock { Text = badgeText, FontSize = 11, Foreground = Brushes.White },
+        });
+        stack.Children.Add(header);
+
+        stack.Children.Add(new TextBlock
+        {
+            Text = $"입력: {string.Join(", ", provider.Capability.InputExtensions)}  →  출력: {string.Join(", ", provider.Capability.OutputExtensions)}",
+            FontSize = 11,
+            Foreground = (Brush)Application.Current.FindResource("TextFillColorTertiaryBrush"),
+            Margin = new Thickness(0, 4, 0, 0),
+        });
+        if (!availability.IsReady && !string.IsNullOrEmpty(availability.Reason))
+        {
+            stack.Children.Add(new TextBlock
+            {
+                Text = availability.Reason,
+                FontSize = 11,
+                Foreground = (Brush)Application.Current.FindResource("BadgeWarnBrush"),
+                TextWrapping = TextWrapping.Wrap,
+                Margin = new Thickness(0, 4, 0, 0),
+            });
+        }
+        card.Content = stack;
+        return card;
+    }
+
+    private async void OnRefreshClick(object sender, RoutedEventArgs e) => await PopulateAsync();
+    private void OnCloseClick(object sender, RoutedEventArgs e) => Close();
+}