Added mailboxes as local data sources (#1022)

app/MindWork AI Studio/Settings/IIndexedDataSource.cs

@@ -0,0 +1,35 @@
+using AIStudio.Provider;
+
+namespace AIStudio.Settings;
+
+/// <summary>
+/// A data source whose content AI Studio embeds and indexes itself.
+/// </summary>
+/// <remarks>
+/// The embedding signature, the chunking and the embedding provider are worked out from these
+/// members alone. That is why the indexer serves every data source implementing this interface,
+/// whether it is stored in DataSources or not.
+/// </remarks>
+public interface IIndexedDataSource : IDataSourceBase
+{
+    /// <summary>
+    /// Which provider confidence level is required by this data source?
+    /// </summary>
+    public ConfidenceLevel ConfidenceLevel { get; init; }
+
+    /// <summary>
+    /// The unique identifier of the embedding provider used by this data source.
+    /// </summary>
+    public string EmbeddingId { get; init; }
+
+    /// <summary>
+    /// Optional maximum number of tokens per embedding chunk for this data source.
+    /// A value of 0 means the embedding provider's setting is used.
+    /// </summary>
+    public int MaxChunkTokenLength { get; init; }
+
+    /// <summary>
+    /// Optional number of tokens to overlap between consecutive chunks.
+    /// </summary>
+    public int ChunkOverlapTokenLength { get; init; }
+}