feat(search): weight subject above body in FTS vector (#14)

src/InboxIntel.Infrastructure/Migrations/20260701192100_WeightSearchVectorSubjectBody.cs

@@ -0,0 +1,45 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+using NpgsqlTypes;
+
+#nullable disable
+
+namespace InboxIntel.Infrastructure.Migrations
+{
+    /// <inheritdoc />
+    public partial class WeightSearchVectorSubjectBody : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<NpgsqlTsVector>(
+                name: "SearchVector",
+                table: "emails",
+                type: "tsvector",
+                nullable: true,
+                computedColumnSql: "setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')",
+                stored: true,
+                oldClrType: typeof(NpgsqlTsVector),
+                oldType: "tsvector",
+                oldNullable: true,
+                oldComputedColumnSql: "to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))",
+                oldStored: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AlterColumn<NpgsqlTsVector>(
+                name: "SearchVector",
+                table: "emails",
+                type: "tsvector",
+                nullable: true,
+                computedColumnSql: "to_tsvector('english', coalesce(\"Subject\",'') || ' ' || coalesce(\"BodyText\",''))",
+                stored: true,
+                oldClrType: typeof(NpgsqlTsVector),
+                oldType: "tsvector",
+                oldNullable: true,
+                oldComputedColumnSql: "setweight(to_tsvector('english', coalesce(\"Subject\",'')), 'A') || setweight(to_tsvector('english', coalesce(\"BodyText\",'')), 'B')",
+                oldStored: true);
+        }
+    }
+}