feat: migrate IM identity and snowflake primary keys

server/db/mysql/group_schema_test.go

@@ -30,4 +30,14 @@ func TestEnsureIMGroupBusinessTablesUsesSelectedTenantDatabase(t *testing.T) {
 			t.Fatalf("group schema must use the selected tenant database: %s", statement)
 		}
 	}
+	joined := strings.ToLower(strings.Join(exec.statements, "\n"))
+	for _, expected := range []string{
+		"primary key(id), unique index uk_im_group_settings_topic(topic)",
+		"primary key(id), unique index uk_im_group_announcement_reads_announcement_user(announcement_id, user_id)",
+		"primary key(id), unique index uk_im_group_mutes_topic_user(topic, user_id)",
+	} {
+		if !strings.Contains(joined, expected) {
+			t.Fatalf("group schema is missing snowflake primary-key definition %q", expected)
+		}
+	}
 }