Removed the denormalized data source name from the RAG storage (#977)

app/MindWork AI Studio/Tools/Databases/IndexStore/Migrations/20260916000000_DropDataSourceName.cs

@@ -0,0 +1,36 @@
+#nullable disable
+
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace AIStudio.Tools.Databases.IndexStore.Migrations;
+
+/// <summary>
+/// Drops the copy of the data source name which the index kept next to each indexed data source.
+/// </summary>
+/// <remarks>
+/// The name a user gives a data source lives in the configuration and is read from there whenever
+/// it is needed. The copy here was only ever written, never read, and a copy of a name people are
+/// free to change can do nothing but go stale.
+/// </remarks>
+[DbContext(typeof(IndexStoreDbContext))]
+[Migration("20260916000000_DropDataSourceName")]
+public partial class DropDataSourceName : Migration
+{
+    /// <remarks>
+    /// The column goes through raw SQL instead of DropColumn on purpose. The SQLite provider answers
+    /// DropColumn by rebuilding the table, and dropping the old data_sources table would let the
+    /// cascade of the foreign key in embedded_files take every indexed file and chunk with it. A
+    /// native ALTER TABLE ... DROP COLUMN leaves the table itself alone. No index names this column,
+    /// so nothing has to be dropped first.
+    /// </remarks>
+    protected override void Up(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.Sql("ALTER TABLE data_sources DROP COLUMN data_source_name;");
+    }
+
+    protected override void Down(MigrationBuilder migrationBuilder)
+    {
+        migrationBuilder.Sql("ALTER TABLE data_sources ADD COLUMN data_source_name TEXT NOT NULL DEFAULT '';");
+    }
+}

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

@@ -23,11 +23,6 @@ partial class IndexStoreDbContextModelSnapshot : ModelSnapshot
                 .HasColumnType("TEXT")
                 .HasColumnName("data_source_id");
 
-            entity.Property<string>("DataSourceName")
-                .IsRequired()
-                .HasColumnType("TEXT")
-                .HasColumnName("data_source_name");
-
             entity.Property<string>("DataSourceType")
                 .IsRequired()
                 .HasColumnType("TEXT")
@@ -274,10 +269,6 @@ partial class IndexStoreDbContextModelSnapshot : ModelSnapshot
                 .IsRequired()
                 .HasColumnType("TEXT");
 
-            entity.Property<string>("DataSourceName")
-                .IsRequired()
-                .HasColumnType("TEXT");
-
             entity.Property<string>("DataSourceType")
                 .IsRequired()
                 .HasColumnType("TEXT");