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/admin-alerts.test.ts

@@ -3,6 +3,7 @@ import { revalidatePath } from "next/cache";
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import { requirePermission } from "@/lib/admin/guard";
 import { rcon } from "@/lib/services/rcon";
+import { fakeForm } from "@/test/fake-form";
 import { sendHotelAlert } from "./admin-alerts";
 
 vi.mock("@/lib/admin/guard", () => ({ requirePermission: vi.fn() }));
@@ -18,10 +19,6 @@ vi.mock("@/lib/db", () => ({
 vi.mock("@/lib/services/rcon", () => ({ rcon: { send: vi.fn() } }));
 vi.mock("next/cache", () => ({ revalidatePath: vi.fn() }));
 
-const fakeForm = (data: Record<string, string>) => ({
-	get: (key: string) => data[key] ?? null,
-});
-
 beforeEach(() => {
 	vi.clearAllMocks();
 	vi.mocked(requirePermission).mockResolvedValue({
@@ -33,15 +30,13 @@ beforeEach(() => {
 
 describe("sendHotelAlert", () => {
 	it("sends hotel alert and revalidates", async () => {
-		await sendHotelAlert(
-			fakeForm({ message: "Hello!" }) as unknown as FormData,
-		);
+		await sendHotelAlert(fakeForm({ message: "Hello!" }) as FormData);
 		expect(rcon.send).toHaveBeenCalledWith("hotelalert", { message: "Hello!" });
 		expect(revalidatePath).toHaveBeenCalledWith("/admin/alerts");
 	});
 
 	it("returns early when message is empty", async () => {
-		await sendHotelAlert(fakeForm({ message: "" }) as unknown as FormData);
+		await sendHotelAlert(fakeForm({ message: "" }) as FormData);
 		expect(rcon.send).not.toHaveBeenCalled();
 	});
 });