feat(strategy): expose configurable nick contract

tests/test_strategy_catalog_postgres_integration.py

@@ -6,7 +6,6 @@ PostgreSQL endpoint. Normal unit-test environments skip this module.
 
 from __future__ import annotations
 
-import hashlib
 import os
 import subprocess
 import threading
@@ -73,9 +72,12 @@ def _prepare_catalog_fixture(repo: PostgresPortfolioRepository) -> tuple[str, st
     return strategy.id, asset_id, owner_user_id
 
 
-def test_concurrent_strategy_patch_keeps_derived_nick_consistent() -> None:
+def test_concurrent_strategy_patch_preserves_existing_nick() -> None:
     owner = _repo()
     strategy_id, asset_id, owner_user_id = _prepare_catalog_fixture(owner)
+    initial = owner.get_strategy_set(strategy_id)
+    assert initial is not None
+    initial_nick = initial.nick
     renamed = f"concurrent-renamed-{uuid.uuid4().hex}"
     barrier = threading.Barrier(3)
     errors: list[BaseException] = []
@@ -114,8 +116,7 @@ def test_concurrent_strategy_patch_keeps_derived_nick_consistent() -> None:
     assert final.name == renamed
     assert final.config == '{"window":21}'
     assert final.revision == 3
-    expected_nick = f"{final.name}:{hashlib.sha1(final.config.encode()).hexdigest()[:12]}"
-    assert final.nick == expected_nick
+    assert final.nick == initial_nick
     portfolio_id = str(uuid.uuid4())
     owner.create_portfolio(
         portfolio_id,