Thin standalone entry for pre-seeding N accounts before the first
harness run. Wraps SessionPool.seed and writes .env.stresstest.
End-to-end verified: ran against local dev with --count=4, all 4
accounts landed in the DB with is_test_account=TRUE, cred file
written with correct format.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
