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/commandocentrum.ts

@@ -3,7 +3,7 @@
 import { eq, sql } from "drizzle-orm";
 import { revalidatePath } from "next/cache";
 import { z } from "zod";
-import { db, User } from "@/lib/db";
+import { db, queryRows, User } from "@/lib/db";
 import { PERMS } from "@/lib/permissions";
 import { adminAction } from "@/lib/safe-action";
 import { ActionError, actionOk } from "@/lib/safe-action-shared";
@@ -209,10 +209,9 @@ export const setRank = adminAction(
 
 		let rankExists: { id: number }[] = [];
 		try {
-			const [rows] = await db.execute(
+			rankExists = await queryRows<{ id: number }>(
 				sql`SELECT id FROM permission_ranks WHERE id = ${ctx.data.rank} LIMIT 1`,
 			);
-			rankExists = rows as unknown as { id: number }[];
 		} catch {
 			rankExists = [];
 		}