Test and linting tidy-up

tests/test_message_prefix_claim.py

@@ -3,7 +3,7 @@
 import pytest
 
 from app.database import Database
-from app.repository import MessageRepository
+from app.repository import ContactRepository, MessageRepository
 
 
 @pytest.fixture
@@ -29,6 +29,9 @@ async def test_claim_prefix_promotes_dm_to_full_key(test_db):
     full_key = "a1b2c3d3ba9f5fa8705b9845fe11cc6f01d1d49caaf4d122ac7121663c5beec7"
     prefix = full_key[:6].upper()
 
+    # Create the contact so the claim safety check (exactly 1 contact matches prefix) passes
+    await ContactRepository.upsert({"public_key": full_key, "name": "Test"})
+
     msg_id = await MessageRepository.create(
         msg_type="PRIV",
         text="hello",