Broadcast Text pull-out (Live screen) + launch geometry 1920x1040/1366x768 with restore

Models/BroadcastMetadata.cs

@@ -0,0 +1,20 @@
+using System;
+
+namespace ytLive.Models;
+
+/// <summary>The creator-editable broadcast metadata (TASK: broadcast pull-out).
+/// These map onto the YouTube liveBroadcast resource's snippet/status parts —
+/// the fields that stay mutable for the whole life of the broadcast. Fields
+/// that only exist pre-launch (scheduledStartTime, contentDetails) are NOT
+/// here by design; see ai.md "Broadcast metadata side pull-out".</summary>
+public sealed class BroadcastMetadata
+{
+    public string Title { get; set; } = string.Empty;
+    public string Description { get; set; } = string.Empty;
+    public string TagsCsv { get; set; } = string.Empty;
+    /// <summary>"private" / "unlisted" / "public".</summary>
+    public string Visibility { get; set; } = "private";
+    public bool MadeForKids { get; set; }
+    /// <summary>Set at Go Live (insert); read-only in the form.</summary>
+    public DateTime? ScheduledStartTime { get; set; }
+}