TASK 5 items 1-3: reusable stream, health banner, docs refresh

- Reusable stream: GetOrCreateReusableStreamAsync, cached via LayoutStore, bound at broadcast insert
- Health monitoring: GetStreamHealthAsync polls liveStreams.status, report-by-exception banner
- Go-live order: ensure stream → create broadcast → then start pump (URL must exist first)
- Full broadcast form scoped (TASK 5 items 6-7) in TASKS.md + ai.md
- TASK 23 trimmed to technical scope, TASK 26 added (marcom/launch kit)
- Confidential files: MONETIZATION.md + MARCOM.md (gitignored, not committed)
- .gitignore updated for confidential business files
- HANDOFF.md updated with session state and next steps

Services/LayoutStore.cs

@@ -615,6 +615,35 @@ public class LayoutStore : IDisposable
         insert.ExecuteNonQuery();
     }
 
+    /// <summary>The cached reusable stream (TASK 5), or null if never created.
+    /// Survives restarts so the pump has its RTMP URL the moment go-live starts
+    /// instead of waiting on the YouTube round-trip.</summary>
+    public ReusableStream? LoadReusableStream()
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "SELECT Value FROM Settings WHERE Key = 'ReusableStream';";
+        var value = cmd.ExecuteScalar() as string;
+        if (string.IsNullOrWhiteSpace(value)) return null;
+
+        var parts = value.Split('\u001F');
+        return parts.Length == 3
+            ? new ReusableStream(parts[0], parts[1], parts[2])
+            : null;
+    }
+
+    public void SaveReusableStream(ReusableStream? stream)
+    {
+        using var cmd = _connection.CreateCommand();
+        cmd.CommandText = "DELETE FROM Settings WHERE Key = 'ReusableStream';";
+        cmd.ExecuteNonQuery();
+        if (stream == null) return;
+
+        using var insert = _connection.CreateCommand();
+        insert.CommandText = "INSERT INTO Settings (Key, Value) VALUES ('ReusableStream', $value);";
+        insert.Parameters.AddWithValue("$value", $"{stream.Id}\u001F{stream.IngestionAddress}\u001F{stream.StreamName}");
+        insert.ExecuteNonQuery();
+    }
+
     public void Save(IEnumerable<Scene> scenes, Webcam? webcam, SocialsConfig? socials, Music? music = null)
     {
         using var tx = _connection.BeginTransaction();