fix: remove contradictory vi.unmock breaking recover DB fallback tests

The test file had both vi.unmock and vi.mock for the same module.
vi.unmock takes precedence in Vitest, so getAllKeys was the real
function instead of a mock, causing mockReturnValueOnce to fail.

src/__tests__/recover-db-fallback.test.ts

@@ -1,7 +1,5 @@
 import { describe, it, expect, vi, beforeEach } from "vitest";
 
-// Unmock keys to use real getAllKeys (but we'll mock it ourselves)
-vi.unmock("../services/keys.js");
 // verification.js and email.js are mocked below
 
 vi.mock("../services/db.js", () => ({