feat(strategy): expose configurable nick contract

app/repositories/portfolio_repository.py

@@ -243,7 +243,14 @@ class PortfolioRepository(Protocol):
 
     def get_or_create_strategy_set(self, name: str, config: str) -> StrategySet: ...
 
-    def create_strategy_set(self, name: str, config: str, *, status: str = "active") -> StrategySet: ...
+    def create_strategy_set(
+        self,
+        name: str,
+        config: str,
+        *,
+        nick: str | None = None,
+        status: str = "active",
+    ) -> StrategySet: ...
 
     def get_strategy_set(self, id: str) -> StrategySet | None: ...
 
@@ -254,6 +261,7 @@ class PortfolioRepository(Protocol):
         id: str,
         *,
         name: str | None = None,
+        nick: str | None = None,
         config: str | None = None,
         status: str | None = None,
     ) -> StrategySet: ...