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/password-reset.test.ts

@@ -16,24 +16,26 @@ vi.mock("next/navigation", () => ({
 	},
 }));
 
-vi.mock("@/lib/db", () => ({
-	db: {
-		select: vi.fn(() => ({
-			from: vi.fn(() => ({
-				where: vi.fn(() => ({
-					limit: selectLimit,
+vi.mock("@/lib/db", () => {
+	return {
+		db: {
+			select: vi.fn(() => ({
+				from: vi.fn(() => ({
+					where: vi.fn(() => ({
+						limit: selectLimit,
+					})),
 				})),
 			})),
-		})),
-		insert: vi.fn(() => ({
-			values: vi.fn(() => ({
-				onDuplicateKeyUpdate: insertOnDup,
+			insert: vi.fn(() => ({
+				values: vi.fn(() => ({
+					onDuplicateKeyUpdate: insertOnDup,
+				})),
 			})),
-		})),
-	},
-	User: { id: "id", mail: "mail" },
-	PasswordReset: { email: "email", token: "token", createdAt: "createdAt" },
-}));
+		},
+		User: { id: "id", mail: "mail" },
+		PasswordReset: { email: "email", token: "token", createdAt: "createdAt" },
+	};
+});
 
 vi.mock("@/lib/services/email", () => ({
 	sendMail: mockSendMail,