Migrate all test files from resetTestData(t) to testutils.SetupTestDB(t) for isolated per-package test databases. - Add new feature tests: name history assertions, referral discount preview, time blockers, email validation, GDPR export, loyalty manual redemption - Update existing tests to use batch queries and SetupTestDB - Remove test_helpers.go resetTestData infrastructure - Add comprehensive user profile tests (442 new lines) Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>