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/lib/services/repair-nitros.ts

@@ -1,7 +1,7 @@
 import { existsSync, promises as fs } from "node:fs";
 import os from "node:os";
 import { sql } from "drizzle-orm";
-import { db } from "@/lib/db";
+import { queryRows } from "@/lib/db";
 import {
 	type CloneSource,
 	DEFAULT_NITRO_SOURCES,
@@ -167,19 +167,9 @@ export async function repairMissingNitros(
 		interaction_type: string;
 	}>;
 	try {
-		const [rows] = (await db.execute(sql`
+		items = await queryRows<(typeof items)[number]>(sql`
 			SELECT id, item_name, public_name, type, interaction_type FROM items_base ORDER BY id
-		`)) as unknown as [
-			Array<{
-				id: number;
-				item_name: string;
-				public_name: string;
-				type: string;
-				interaction_type: string;
-			}>,
-			unknown,
-		];
-		items = rows;
+		`);
 	} catch (err) {
 		onEvent?.({
 			type: "error",