Added transcription of audio and video files to local data sources (#1081)

Co-authored-by: Paul Koudelka <106623909+PaulKoudelka@users.noreply.github.com>

app/MindWork AI Studio/Tools/Databases/IndexStore/Migrations/20261018000000_MediaTranscriptKey.cs

@@ -0,0 +1,35 @@
+#nullable disable
+
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace AIStudio.Tools.Databases.IndexStore.Migrations;
+
+/// <summary>
+/// Adds the key of the transcript to the indexed files, for audio and video files which a data source transcribed.
+/// </summary>
+/// <remarks>
+/// The transcripts lie below the data directory under the hash of the content of their media file.
+/// The index has to know which transcript belongs to which file, so that AI Studio can remove a
+/// transcript once its file is gone or changed. Every other file keeps NULL.
+/// </remarks>
+[DbContext(typeof(IndexStoreDbContext))]
+[Migration("20261018000000_MediaTranscriptKey")]
+public partial class MediaTranscriptKey : Migration
+{
+    /// <remarks>
+    /// Both directions go through raw SQL, like DropDataSourceName: the SQLite provider answers
+    /// DropColumn by rebuilding the table, and dropping the old embedded_files table would let the
+    /// cascade of the foreign key in embedding_chunks take every chunk with it. Adding a nullable
+    /// column is native in SQLite and leaves the rows alone.
+    /// </remarks>
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.Sql("ALTER TABLE embedded_files ADD COLUMN transcript_key TEXT NULL;");
+    }
+
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.Sql("ALTER TABLE embedded_files DROP COLUMN transcript_key;");
+    }
+}

app/MindWork AI Studio/Tools/Databases/IndexStore/Migrations/IndexStoreDbContextModelSnapshot.cs

@@ -119,6 +119,10 @@ partial class IndexStoreDbContextModelSnapshot : ModelSnapshot
                 .HasColumnType("TEXT")
                 .HasColumnName("relative_path");
 
+            entity.Property<string>("TranscriptKey")
+                .HasColumnType("TEXT")
+                .HasColumnName("transcript_key");
+
             entity.HasKey("ParentFileId");
 
             entity.HasIndex("AbsolutePath")