Fix remaining game model test failures

- Added host_id field to GameHistory model
- Changed players relationship to lazy='selectin' for async compatibility
- All 28 tests now pass

backend/state.json

@@ -1,5 +1,5 @@
 {
-  "project_summary": "MTG Online backend API with FastAPI, SQLAlchemy, and SQLite. Phase 5 development complete with all deck tests passing.",
+  "project_summary": "MTG Online backend API with FastAPI, SQLAlchemy, and SQLite. Phase 5 development complete with all 28 tests passing.",
   "roadmap": [
     {"phase": "Phase 1-4", "status": "completed"},
     {"phase": "Phase 5 - Game Management", "status": "completed"},
@@ -13,22 +13,22 @@
     "auth": "JWT (python-jose)"
   },
   "architectural_notes": "Single-process FastAPI app with async SQLAlchemy. SQLite for development/testing. JWT auth with user roles.",
-  "task_description": "Fix remaining deck test failures",
-  "current_step": "All deck tests passing",
+  "task_description": "Fix remaining game model test failures",
+  "current_step": "All 28 tests passing",
   "files_created": [],
   "files_modified": [
-    "tests/conftest.py",
     "app/models/models.py"
   ],
   "decisions": [
     "Use execution_options for implicit_returning in SQLAlchemy 2.0",
-    "Use datetime.now instead of func.now() for async serialization"
+    "Use datetime.now instead of func.now() for async serialization",
+    "Use lazy='selectin' for async-safe relationship loading",
+    "Add host_id field to GameHistory model"
   ],
   "next_steps": [
-    "Run full test suite to verify all tests pass",
-    "Address remaining 2 game model test failures"
+    "Phase 6 - WebSocket Game Server"
   ],
   "blockers": [],
   "commit_hash": "f7d6bfd",
-  "timestamp": "2026-10-18T03:40:00Z"
+  "timestamp": "2026-10-18T04:02:00Z"
 }