refactor(db): typed query helpers, shared test FormData helper

Replace raw db.execute tuple casts with queryRows/rowsFrom/execResult/
affectedRows helpers from lib/db, drop redundant mysql2 casts on typed
query builders, and centralize per-test fakeForm into test/fake-form.
Update db mocks in tests so helpers resolve against mocked execute.

src/actions/permissions.ts

@@ -1,7 +1,6 @@
 "use server";
 
 import { and, count, eq, inArray, sql } from "drizzle-orm";
-import type { ResultSetHeader } from "mysql2";
 import { revalidateTag } from "next/cache";
 import { z } from "zod";
 import {
@@ -254,9 +253,9 @@ export const repairAdminNavAclGrants = adminAction(
 		`);
 
 		const inserted =
-			Number((dashboardFillResult as ResultSetHeader).affectedRows) +
-			Number((midRankViewsResult as ResultSetHeader).affectedRows) +
-			Number((highRankToolsResult as ResultSetHeader).affectedRows);
+			Number(dashboardFillResult.affectedRows) +
+			Number(midRankViewsResult.affectedRows) +
+			Number(highRankToolsResult.affectedRows);
 
 		await logStaffActivity({
 			staffId: ctx.session.user.id,