feat(text): persist independent text layer settings

Add additive defaults and round-trip tests for per-layer text content and formatting. Model the static text source after OBS text-source conventions: https://obsproject.com/kb/text-sources

Models/Source.cs

@@ -41,6 +41,13 @@ public enum MediaPlaybackState
     Paused
 }
 
+public enum TextLayerAlignment
+{
+    Left,
+    Center,
+    Right
+}
+
 public enum ClipShape
 {
     Traditional,
@@ -391,6 +398,58 @@ public class Source : SceneElement
 
     public override bool IsChatBox => Type == SourceType.ChatBox;
 
+    private string _textContent = "Text";
+    public string TextContent
+    {
+        get => _textContent;
+        set => Set(ref _textContent, value ?? string.Empty);
+    }
+
+    private string _textFontFamily = "Segoe UI";
+    public string TextFontFamily
+    {
+        get => _textFontFamily;
+        set => Set(ref _textFontFamily, string.IsNullOrWhiteSpace(value) ? "Segoe UI" : value.Trim());
+    }
+
+    private double _textFontSize = 48;
+    public double TextFontSize
+    {
+        get => _textFontSize;
+        set => Set(ref _textFontSize, double.IsFinite(value) ? Math.Clamp(value, 8, 300) : 48);
+    }
+
+    private string _textColor = "#FFFFFF";
+    public string TextColor
+    {
+        get => _textColor;
+        set => Set(ref _textColor, IsValidTextColor(value) ? value.ToUpperInvariant() : "#FFFFFF");
+    }
+
+    private bool _textBold;
+    public bool TextBold { get => _textBold; set => Set(ref _textBold, value); }
+
+    private bool _textItalic;
+    public bool TextItalic { get => _textItalic; set => Set(ref _textItalic, value); }
+
+    private bool _textUnderline;
+    public bool TextUnderline { get => _textUnderline; set => Set(ref _textUnderline, value); }
+
+    private TextLayerAlignment _textAlignment;
+    public TextLayerAlignment TextAlignment
+    {
+        get => _textAlignment;
+        set => Set(ref _textAlignment, Enum.IsDefined(value) ? value : TextLayerAlignment.Left);
+    }
+
+    private static bool IsValidTextColor(string? value)
+    {
+        if (value is not { Length: 7 or 9 } || value[0] != '#') return false;
+        for (var i = 1; i < value.Length; i++)
+            if (!Uri.IsHexDigit(value[i])) return false;
+        return true;
+    }
+
     public override bool IsCountdown => Type == SourceType.Countdown;
 
     private bool _chatPreviewEnabled = true;

Models/index.md

@@ -7,7 +7,7 @@ Plain data types. No logic beyond what a property can carry. See
 |------|---------|
 | `Scene.cs` | A scene: `Name`, `IsHidden`, `IsChatScene`, `IsEditing`, **`HasBackdrop`** (Live-only policy flag, default off — only the canonical Live scene has one, see `SceneCatalog`), `Elements` collection (images + webcam config), `WebcamConfig` accessor |
 | `SceneCatalog.cs` | The five canonical scenes (Starting/Live/BRB/Chat/Ending) — the product, by name: `All`, `IsCanonical`, `Is(name, canonical)` (case-insensitive trim), `IsChat`, `HasBackdrop(name)` (true only for Live). Drives the empty-DB seed, the "+" missing-scenes menu, and `MainViewModel.EnforceBackdropPolicy` |
-| `Source.cs` | A source: `SourceType` enum (DisplayCapture/WindowCapture/Background/Image/TextOverlay/ChatBox/Countdown/WebSource/MediaSource/**AlertBox (one per layout)**/**Ticker (one per scene)**/Blur), `X`/`Y`/`Width`/`Height`, `Opacity`, `IsEnabled`, `ImageSource` (static) / `VideoImageSource` (live frames), `DisplaySource` (`IsLiveCapture` → video, else static), `ClipShape` enum (Traditional/Round), `IsMirrored` + `MirrorScale`, `MirrorButtonText`, asset identity, `IsImageSource` (XAML binds this, never `Type`), **backdrop surface**: `IsBackdrop` (permanent bottom layer, never removable), `CaptureKey` (persisted `monitor:<n>`/`window:<hwnd>`/`picker:<name>`), `IsLiveCapture` (`Type` is Display/WindowCapture); each source owns `Ticker` settings, with AlertBox compatibility properties persisted on that source row |
+| `Source.cs` | A source: `SourceType` enum (DisplayCapture/WindowCapture/Background/Image/TextOverlay/ChatBox/Countdown/WebSource/MediaSource/**AlertBox (one per layout)**/**Ticker (one per scene)**/Blur), `X`/`Y`/`Width`/`Height`, `Opacity`, `IsEnabled`, `ImageSource` (static) / `VideoImageSource` (live frames), `DisplaySource` (`IsLiveCapture` → video, else static), `ClipShape` enum (Traditional/Round), `IsMirrored` + `MirrorScale`, `MirrorButtonText`, asset identity, `IsImageSource` (XAML binds this, never `Type`), **TextOverlay content + font/size/color/emphasis/alignment settings** (independent per source; static text), **backdrop surface**: `IsBackdrop` (permanent bottom layer, never removable), `CaptureKey` (persisted `monitor:<n>`/`window:<hwnd>`/`picker:<name>`), `IsLiveCapture` (`Type` is Display/WindowCapture); each source owns `Ticker` settings, with AlertBox compatibility properties persisted on that source row |
 | `Ticker.cs` | Shared per-source ticker settings: `IsEnabled` and `DisplayMethod`; one independent instance for each scene ticker and the AlertBox ticker |
 | `SceneElement.cs` | Base for anything placeable in a scene: shared layout/clip/mirror/border surface, `virtual IsWebcam`/`virtual IsImageSource`/`virtual IsZoomLayer` (TASK 52); `ToggleClipShape` + persisted `RectWidth`/`RectHeight` (pre-Round rect so round→rect restores after reload); **TASK 57:** the geometry setters (`X`/`Y`/`Width`/`Height`) are `virtual` so a derived element can CONSTRAIN every write (the webcam clamps itself into the vertical tier's band) instead of every writer re-implementing the rule; `ClipShape` + `ToggleClipShape()` are `virtual` too, so a derived element can CONSTRAIN the shape (the Chat scene's vertical camera is rect-only); **TASK 59:** `IsRectShape`/`IsRoundShape` — the shape as a CHOICE (the properties panel shows Rect | Circle with Rect selected by default), each a settable bool whose setter flips the shape through `ToggleClipShape()` and always re-raises, so the UI snaps back when a write is refused; **TASK 63:** `BorderColorEntry` (the palette entry for the current border colour — hex + NAME, a nameless entry for a custom hex; setting it writes the hex back) and `BorderColorOptions` (the palette + that entry), both raised when `BorderColor` changes — the drop-down binds to them |
 | `VerticalCameraLayout.cs` | **TASK 57 (the "vv" feature):** the vertical (9:16) tier's camera rules as pure math — `TileWidth`/`TileHeight` (270×152 master px = 480×270 in the 1080×1920 output), `Inset` (32 master px from the band's outer edge), `IsVerticalTier(QualityOption)` (portrait tier), `AreaFor(band, bottom)` (the band splits into two 607×540 areas), `MaxSizeFor(band)`, `SpotFor(band, w, h, centreX, centreY)` (the six spots — the area and column the tile's **centre** falls in, inset, never outside the band) and `DefaultSpot` (bottom-right, the corner the 16:9 default webcam uses), `FillsArea(band, width)` (the camera is wide enough to fill a whole area = "enlarged") and `SizeFor(band, requestedWidth)` (the Chat camera's TWO sizes - the small tile or one whole 607×540 area — whichever is nearer the requested width, so the resize handle has two detents) |