Added mailboxes as local data sources (#1022)

app/MindWork AI Studio/Settings/DataModel/OutboundDataRequirement.cs

@@ -0,0 +1,31 @@
+namespace AIStudio.Settings.DataModel;
+
+/// <summary>
+/// Where a chat may still send data, and which data source demands it.
+/// </summary>
+/// <remarks>
+/// The data source travels along so a tool which is kept from running can name it, and the user
+/// learns which mailbox stands in the way. It is its id rather than its name, because a mailbox
+/// may be renamed after a chat read from it.
+/// </remarks>
+/// <param name="Restriction">Where the chat may still send data.</param>
+/// <param name="DataSourceId">The id of the data source which demands the restriction, or an empty text when nothing restricts the chat.</param>
+public sealed record OutboundDataRequirement(OutboundDataRestriction Restriction, string DataSourceId)
+{
+    /// <summary>
+    /// Demands nothing: what a chat holds before it read from any mailbox, and what a result
+    /// demands which brought no content of one in.
+    /// </summary>
+    public static readonly OutboundDataRequirement NONE = new(OutboundDataRestriction.UNRESTRICTED, string.Empty);
+
+    /// <summary>
+    /// The stricter of this requirement and another one.
+    /// </summary>
+    /// <remarks>
+    /// On a tie, this one is kept, so the data source which set a level first stays the one which
+    /// is named, and a chat does not name another mailbox with every search.
+    /// </remarks>
+    /// <param name="other">The other requirement.</param>
+    /// <returns>The requirement whose restriction is the stricter one.</returns>
+    public OutboundDataRequirement StricterOf(OutboundDataRequirement other) => other.Restriction < this.Restriction ? other : this;
+}