Test migration discovery: every Migration subclass is listed, in order

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

tests/Bifrost.Web.Tests/MigrationDiscoveryTests.cs

@@ -0,0 +1,56 @@
+using Bifrost.Web.Data;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+namespace Bifrost.Web.Tests;
+
+public sealed class MigrationDiscoveryTests
+{
+    private static readonly string[] ExpectedMigrations =
+    [
+        "20260422084653_InitialAlphaFoundation",
+        "20260608210000_AddHeimdallUserIdentity",
+        "20260609143000_AddPatronSupportDerivation",
+        "20260609160000_AddExternalPatronProviderIntake",
+        "20260617010537_AddBridgeActionLedger",
+        "20260617022305_AddAgentDispatchRuns",
+        "20260617033635_AddAgentTransportReceipts",
+        "20260617041417_AddGovernanceActivityReceipts",
+        "20260622142000_AddBridgeActionIdentityProvenance",
+        "20260622165000_AddBifrostNativeIdentity",
+        "20260622202000_AddBridgeActionTargetSurfaceName",
+        "20260705190000_AddPatronSupportProjectAttribution",
+    ];
+
+    // Database.GetMigrations() reads assembly metadata only; no connection is opened.
+    private static List<string> Discovered()
+    {
+        var options = new DbContextOptionsBuilder<BifrostDbContext>()
+            .UseNpgsql("Host=unused")
+            .Options;
+        using var db = new BifrostDbContext(options);
+        return db.Database.GetMigrations().ToList();
+    }
+
+    [Fact]
+    public void Every_migration_type_is_discovered()
+    {
+        var discovered = Discovered();
+        var declared = typeof(BifrostDbContext).Assembly.GetTypes()
+            .Where(t => !t.IsAbstract && typeof(Migration).IsAssignableFrom(t))
+            .ToList();
+
+        Assert.NotEmpty(declared);
+        Assert.Equal(declared.Count, discovered.Count);
+        foreach (var type in declared)
+        {
+            Assert.Contains(discovered, id => id.EndsWith("_" + type.Name, StringComparison.Ordinal));
+        }
+    }
+
+    [Fact]
+    public void All_twelve_migrations_are_listed_in_order()
+    {
+        Assert.Equal(ExpectedMigrations, Discovered());
+    }
+}