feat(cfold): canonicalize custom test layout

tests/mailu/functional/test_mailbox.py

@@ -1,29 +0,0 @@
-"""mailu — recipe-specific functional test #1 (Phase 2 P3 §4.3 create-an-object + read-back).
-
-Create a mailbox (the characteristic mailu object) via the admin CLI, then read it back from the
-authoritative config export and assert it is present. Real create→persist→read-back, not health-only.
-"""
-
-from __future__ import annotations
-
-import os
-import sys
-import uuid
-
-sys.path.insert(0, os.path.dirname(__file__))
-import _mailu  # noqa: E402
-
-
-def test_create_mailbox_and_read_back(live_app):
-    mail_domain = live_app  # recipe_meta sets MAIL_DOMAIN = the per-run domain
-    local = "ccci-" + uuid.uuid4().hex[:8]
-    password = "CcCi-" + uuid.uuid4().hex[:16] + "-Aa1!"
-
-    _mailu.ensure_domain(live_app, mail_domain)
-    email = _mailu.create_user(live_app, local, mail_domain, password)
-
-    cfg = _mailu.config_export(live_app)
-    emails = _mailu.user_emails(cfg)
-    assert (
-        email in emails
-    ), f"created mailbox {email} not present in mailu config-export users {emails}"