feat(api): expose strategy nick on portfolio items

app/repositories/postgres.py

@@ -73,7 +73,8 @@ _SELECT_PORTFOLIO = """
         ss.name,
         ss.config,
         a.markets,
-        ss.revision
+        ss.revision,
+        ss.nick
     FROM portfolios p
     JOIN assets a ON p.asset_id = a.asset_id
     LEFT JOIN strategy_sets ss ON p.active_strategy_id = ss.id
@@ -572,6 +573,8 @@ class PostgresPortfolioRepository:
         _markets_raw = row[21] if len(row) > 21 else None
         markets: list[str] = list(_markets_raw) if _markets_raw else []
         strategy_revision = int(row[22]) if len(row) > 22 and row[22] is not None else None
+        # REQ-055: strategy_nick (row[23] = ss.nick from LEFT JOIN strategy_sets)
+        strategy_nick: str | None = row[23] if len(row) > 23 else None
 
         return Portfolio(
             portfolio_id=row[0],
@@ -595,6 +598,7 @@ class PostgresPortfolioRepository:
             tag_ids=[str(t) for t in row[17]] if len(row) > 17 and row[17] is not None else [],
             display_name=row[18] if len(row) > 18 else None,
             strategy_name=strategy_name,
+            strategy_nick=strategy_nick,
             strategy_params=strategy_params,
             strategy_revision=strategy_revision,
             markets=markets,