Added mailboxes as local data sources (#1022)

app/MindWork AI Studio/Tools/Services/Indexing/EmbeddingChunk.cs

@@ -0,0 +1,14 @@
+namespace AIStudio.Tools.Services.Indexing;
+
+/// <summary>
+/// One chunk as the chunking produced it, together with the page it starts on.
+/// </summary>
+/// <remarks>
+/// The page is carried rather than read back out of the chunk text. The runtime states it, and
+/// the chunking knows which source segment a chunk begins in, so nothing has to be derived from
+/// a marker in the text — which is what used to leave Word files and continued passages without
+/// a page.
+/// </remarks>
+/// <param name="Text">The chunk itself, overlap prefix included.</param>
+/// <param name="PageNumber">The page the chunk's own content starts on, or null when it has none.</param>
+internal sealed record EmbeddingChunk(string Text, int? PageNumber);