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/features/catalog/server/package-snapshot.ts

@@ -2,6 +2,7 @@ import "server-only";
 import { createHash } from "node:crypto";
 import { sql } from "drizzle-orm";
 import type { db } from "@/lib/db";
+import { rowsFrom } from "@/lib/db";
 import {
 	assertParent,
 	CatalogInputError,
@@ -84,10 +85,11 @@ export async function readPackagePages(
 	tx: PackageTx,
 	lock: boolean,
 ): Promise<SourceRow[]> {
-	const [rows] = await tx.execute(
-		sql`SELECT * FROM catalog_pages ORDER BY id LIMIT 20001${lock ? sql` FOR UPDATE` : sql``}`,
+	const pages = rowsFrom<SourceRow>(
+		await tx.execute(
+			sql`SELECT * FROM catalog_pages ORDER BY id LIMIT 20001${lock ? sql` FOR UPDATE` : sql``}`,
+		),
 	);
-	const pages = rows as unknown as SourceRow[];
 	if (pages.length > 20000)
 		throw new CatalogInputError(
 			"Catalog exceeds package safety limit (20000 categories)",
@@ -128,10 +130,11 @@ export async function readPackageSource(
 	}
 	const selectedPages = pages.filter((p) => selected.has(Number(p.id)));
 	const ids = selectedPages.map((p) => String(p.id));
-	const [rows] = await tx.execute(
-		sql`SELECT * FROM catalog_items WHERE page_id IN (${sql.join(ids, sql`, `)}) ORDER BY id LIMIT 501${lock ? sql` FOR UPDATE` : sql``}`,
+	const offers = rowsFrom<SourceRow>(
+		await tx.execute(
+			sql`SELECT * FROM catalog_items WHERE page_id IN (${sql.join(ids, sql`, `)}) ORDER BY id LIMIT 501${lock ? sql` FOR UPDATE` : sql``}`,
+		),
 	);
-	const offers = rows as unknown as SourceRow[];
 	if (offers.length > 500)
 		throw new CatalogInputError("A package supports at most 500 offers");
 	const furnitureIds = [
@@ -142,11 +145,12 @@ export async function readPackageSource(
 			"Package furniture references exceed safety limit",
 		);
 	if (furnitureIds.length) {
-		const [foundRows] = await tx.execute(
-			sql`SELECT id FROM items_base WHERE id IN (${sql.join(furnitureIds, sql`, `)}) ORDER BY id${lock ? sql` FOR UPDATE` : sql``}`,
-		);
 		const found = new Set(
-			(foundRows as unknown as { id: number }[]).map((row) => Number(row.id)),
+			rowsFrom<{ id: number }>(
+				await tx.execute(
+					sql`SELECT id FROM items_base WHERE id IN (${sql.join(furnitureIds, sql`, `)}) ORDER BY id${lock ? sql` FOR UPDATE` : sql``}`,
+				),
+			).map((row) => Number(row.id)),
 		);
 		if (furnitureIds.some((id) => !found.has(id)))
 			throw new CatalogNotFound("Package furniture reference no longer exists");