Added the visual briefing assistant (#893)

app/MindWork AI Studio/Assistants/VisualBriefing/VisualBriefingSourceCoverageKind.cs

@@ -0,0 +1,25 @@
+using System.Text.Json.Serialization;
+
+namespace AIStudio.Assistants.VisualBriefing;
+
+/// <summary>
+/// Classifies source coverage reported by the content stage.
+/// </summary>
+[JsonConverter(typeof(JsonStringEnumConverter<VisualBriefingSourceCoverageKind>))]
+public enum VisualBriefingSourceCoverageKind
+{
+    /// <summary>
+    /// The source directly contributed facts to the briefing.
+    /// </summary>
+    USED,
+
+    /// <summary>
+    /// The source supplied context without directly contributing visible facts.
+    /// </summary>
+    CONTEXTUAL,
+
+    /// <summary>
+    /// The source is intentionally outside the scope requested by the user.
+    /// </summary>
+    OUT_OF_SCOPE,
+}