Split SwarmUI portraits into a model catalog and layered prompts.

Picker is Swarm intersect config, preset style/shot inherit model defaults, and living saves lift the old preset shape.

tests/HSchool.AppHost.Tests/PortraitApiTests.cs

@@ -102,6 +102,7 @@ public class PortraitApiTests(AppHostFixture fixture)
             TestContext.Current.CancellationToken);
         Assert.NotNull(settings);
         Assert.NotEmpty(settings!.Presets);
+        Assert.NotEmpty(settings.Models);
         Assert.False(string.IsNullOrWhiteSpace(settings.ActivePresetId));
     }
 
@@ -119,6 +120,8 @@ public class PortraitApiTests(AppHostFixture fixture)
         Assert.True(document.RootElement.TryGetProperty("portraitSettings", out var presets));
         Assert.True(presets.TryGetProperty("presets", out var list));
         Assert.True(list.GetArrayLength() > 0);
+        Assert.True(presets.TryGetProperty("models", out var models));
+        Assert.True(models.GetArrayLength() > 0);
     }
 
     [Fact]
@@ -193,9 +196,14 @@ public class PortraitApiTests(AppHostFixture fixture)
         string PresetId,
         string PresetLabel);
 
-    private sealed record SwarmUiSettingsPayload(string ActivePresetId, IReadOnlyList<SwarmUiPresetPayload> Presets);
+    private sealed record SwarmUiSettingsPayload(
+        string ActivePresetId,
+        IReadOnlyList<SwarmUiPresetPayload> Presets,
+        IReadOnlyList<SwarmUiModelPayload> Models);
 
     private sealed record SwarmUiPresetPayload(string Id, string Label);
 
+    private sealed record SwarmUiModelPayload(string Id);
+
     private sealed record SavesDirectoryResponse(string Path);
 }