diff --git a/tradein-mvp/backend/app/schemas/team.py b/tradein-mvp/backend/app/schemas/team.py
index a1022247..fe037389 100644
--- a/tradein-mvp/backend/app/schemas/team.py
+++ b/tradein-mvp/backend/app/schemas/team.py
@@ -16,7 +16,14 @@ from pydantic import BaseModel, ConfigDict, Field, field_validator
 # (`app.core.rbac._propagate_authenticated_user` кодирует latin-1 с
 # errors="replace"), поэтому валидация формы обязательна на границе API,
 # а не только на уровне БД.
-_USERNAME_RE = re.compile(r"^[A-Za-z0-9._-]{3,64}$")
+#
+# `\Z`, НЕ `$` — deep-review seed #2564: в Python `$` матчит перед trailing
+# newline (`re.match(r'...\$', 'admin\n')` → True), а Postgres `~` в CHECK
+# tradein_users_username_ascii_ck (миграция 193) — False. С `$` строка
+# "admin\n" проходила бы Pydantic-валидацию и падала уже в БД → 500 вместо
+# честного 422. `\Z` — конец строки БЕЗ поблажки на trailing newline, совпадает
+# с семантикой Postgres `~`.
+_USERNAME_RE = re.compile(r"^[A-Za-z0-9._-]{3,64}\Z")
 
 
 class QuotaStatusOut(BaseModel):
diff --git a/tradein-mvp/backend/tests/test_team_api.py b/tradein-mvp/backend/tests/test_team_api.py
index 6a446885..2f1e40ce 100644
--- a/tradein-mvp/backend/tests/test_team_api.py
+++ b/tradein-mvp/backend/tests/test_team_api.py
@@ -519,6 +519,26 @@ def test_create_employee_non_ascii_username_422(client: TestClient, store: _Stor
     assert resp.status_code == 422
 
 
+@pytest.mark.parametrize("username", ["admin\n", "user1\n"])
+def test_create_employee_trailing_newline_username_422_not_500(
+    client: TestClient, store: _Store, username: str
+) -> None:
+    """Deep-review seed #2564: Python `$` matches BEFORE a trailing newline
+    (`re.match(r'...\\$', 'admin\\n')` → True), but Postgres `~` (CHECK
+    tradein_users_username_ascii_ck, migration 193) does NOT — a username with a
+    trailing "\\n" used to pass Pydantic validation and crash in the DB (500)
+    instead of a clean 422. `_USERNAME_RE` now uses `\\Z`, matching Postgres `~`
+    semantics exactly."""
+    store.add_user("mgr_a", hash_password("Secret123!"), role="manager")
+    _login(client, "mgr_a", "Secret123!")
+
+    resp = client.post(
+        "/api/v1/team/employees",
+        json={"username": username, "password": "Secret123!"},
+    )
+    assert resp.status_code == 422, resp.text
+
+
 def test_create_employee_duplicate_username_409(client: TestClient, store: _Store) -> None:
     store.add_user("mgr_a", hash_password("Secret123!"), role="manager")
     store.add_user("emp_dup", hash_password("Secret123!"), role="employee")