feat(apps): AppCatalogEntry record + test

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

windows/welcome/src/SilverOS.Welcome.Core/Apps/AppCatalogEntry.cs

@@ -0,0 +1,28 @@
+using System.Text.Json;
+
+namespace SilverOS.Welcome.Core.Apps;
+
+public sealed record AppSource
+{
+    public string? Winget { get; init; }
+    // Future: public string? Mirror { get; init; }  // swappable to a curated mirror.
+}
+
+public sealed record AppCatalogEntry
+{
+    public string Id { get; init; } = "";
+    public string Name { get; init; } = "";
+    public string Description { get; init; } = "";
+    public AppSource Source { get; init; } = new();
+    public string Group { get; init; } = "";
+    public IReadOnlyList<string> Roles { get; init; } = Array.Empty<string>();
+    public IReadOnlyList<string> DefaultFor { get; init; } = Array.Empty<string>();
+    public string? Configure { get; init; }
+
+    public static readonly JsonSerializerOptions JsonOptions = new()
+    {
+        PropertyNameCaseInsensitive = true,
+        ReadCommentHandling = JsonCommentHandling.Skip,
+        AllowTrailingCommas = true
+    };
+}

windows/welcome/tests/SilverOS.Welcome.Tests/AppCatalogTests.cs

@@ -0,0 +1,21 @@
+using System.Text.Json;
+using SilverOS.Welcome.Core.Apps;
+using Xunit;
+
+public class AppCatalogTests
+{
+    [Fact]
+    public void Deserializes_a_catalog_entry()
+    {
+        var json = """
+        { "id":"vscodium","name":"VSCodium","description":"Telemetry-free VS Code.",
+          "source":{"winget":"VSCodium.VSCodium"},"group":"developer",
+          "roles":["developer"],"defaultFor":["developer"],"configure":null }
+        """;
+        var e = JsonSerializer.Deserialize<AppCatalogEntry>(json, AppCatalogEntry.JsonOptions)!;
+        Assert.Equal("vscodium", e.Id);
+        Assert.Equal("VSCodium.VSCodium", e.Source.Winget);
+        Assert.Contains("developer", e.Roles);
+        Assert.Contains("developer", e.DefaultFor);
+    }
+}