Migration clears ConsentReceipts: notice v1 was reused for new words

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

docs/training-notice.md

@@ -11,10 +11,11 @@ fails a test. A reworded notice is version 2, with its own pinned hash.
 
 ## Before deploy
 
-Delete every row from `ConsentReceipts` (and confirm the table is empty) on any database that ever ran main at or after
-`33be966`, before deploying this. Old version 1 receipts were given to different words and would otherwise count as
-agreement to these. Meta/ops must confirm that nothing was ever deployed with receipts in it; if something was, this step is
-required there and the people who agreed are asked again on their next chat sign-in.
+Migration `20261111120000_ClearLegacyConsentReceipts` deletes every row from `ConsentReceipts` when it runs, because
+version 1 receipts were given to different words and must not count as agreement to these. Manual emptying is therefore only
+a belt-and-braces check: confirm the table is empty after the migrate on any database that ever ran main at or after
+`33be966`. Meta/ops must still confirm whether anything was deployed with receipts in it; if so, the people who agreed are
+asked again on their next chat sign-in.
 
 ## What the notice says and why
 

src/Bifrost.Web/Data/Migrations/20261111120000_ClearLegacyConsentReceipts.cs

@@ -0,0 +1,26 @@
+using Bifrost.Web.Data;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace Bifrost.Web.Data.Migrations
+{
+    // Hand-written like AddMembershipSuspensionReason: data only, so no schema change and the snapshot is untouched.
+    // Notice v1 was reused for new words, so any receipt written against the earlier v1 text must not count as agreement
+    // to these. Every row goes; people who agreed are asked again on their next chat sign-in.
+    [DbContext(typeof(BifrostDbContext))]
+    [Migration("20261111120000_ClearLegacyConsentReceipts")]
+    public partial class ClearLegacyConsentReceipts : Migration
+    {
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.Sql("DELETE FROM \"ConsentReceipts\";");
+        }
+
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            // Deleted agreements cannot be restored, and must not be.
+        }
+    }
+}

tests/Bifrost.Web.Tests/MigrationDiscoveryTests.cs

@@ -27,6 +27,7 @@ public sealed class MigrationDiscoveryTests
         "20261111090000_AddConsentReceipts",
         "20261111100000_ConsentReceiptsOneLivePerVersion",
         "20261111110000_AddMembershipSuspensionReason",
+        "20261111120000_ClearLegacyConsentReceipts",
     ];
 
     // Database.GetMigrations() reads assembly metadata only; no connection is opened.