fix(server): populate games_v2 metadata on game start

update_game_started (started_at, num_players, num_rounds, player_ids)
was defined in event_store but had zero callers. 289/289 staging games
had those fields NULL — queries that joined on them returned garbage,
and the denormalized player_ids GIN index was dead weight.

log_game_start now calls create_game THEN update_game_started in one
async task. If create fails, update is skipped (row doesn't exist).
handlers.py passes num_rounds and player_ids through at call time.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

server/test_game_lifecycle_logging.py

@@ -21,7 +21,7 @@ from unittest.mock import AsyncMock, MagicMock, patch
 from game import GameOptions
 from room import Room, RoomManager
 from services.game_logger import GameLogger
-from handlers import ConnectionContext, handle_end_game
+from handlers import ConnectionContext, handle_end_game, handle_start_game
 from test_handlers import MockWebSocket, make_ctx
 
 
@@ -151,6 +151,102 @@ class TestHandleEndGameMarksAbandoned:
 
         ctx = make_ctx(websocket=joiner_ws, player_id="joiner", room=room)
 
+        with patch("handlers.get_logger", return_value=mock_logger):
+            await handle_end_game(
+                {},
+                ctx,
+                room_manager=rm,
+                cleanup_room_profiles=lambda _code: None,
+            )
+
+        mock_logger.log_game_abandoned.assert_not_called()
+        assert room.code in rm.rooms
+
+
+class TestLogGameStartPopulatesMetadata:
+    """
+    create_game only writes id/room_code/host_id/options. update_game_started
+    (which fills in started_at, num_players, num_rounds, player_ids) existed
+    but had zero callers — 100% of staging's 289 games had those fields NULL.
+    log_game_start must call both so the row is complete after start_game.
+    """
+
+    @pytest.mark.asyncio
+    async def test_start_calls_create_and_update(self):
+        event_store = MagicMock()
+        event_store.create_game = AsyncMock()
+        event_store.update_game_started = AsyncMock()
+        logger = GameLogger(event_store)
+        options = GameOptions(initial_flips=0)
+
+        await logger.log_game_start_async(
+            room_code="ABCD",
+            num_players=3,
+            num_rounds=9,
+            player_ids=["p1", "p2", "p3"],
+            options=options,
+        )
+
+        event_store.create_game.assert_awaited_once()
+        event_store.update_game_started.assert_awaited_once()
+        call = event_store.update_game_started.await_args
+        assert call.kwargs.get("num_players", call.args[1] if len(call.args) > 1 else None) == 3
+        assert call.kwargs.get("num_rounds", call.args[2] if len(call.args) > 2 else None) == 9
+        assert call.kwargs.get("player_ids", call.args[3] if len(call.args) > 3 else None) == ["p1", "p2", "p3"]
+
+    @pytest.mark.asyncio
+    async def test_update_uses_same_game_id_as_create(self):
+        event_store = MagicMock()
+        event_store.create_game = AsyncMock()
+        event_store.update_game_started = AsyncMock()
+        logger = GameLogger(event_store)
+
+        await logger.log_game_start_async(
+            room_code="XYZW",
+            num_players=2,
+            num_rounds=1,
+            player_ids=["a", "b"],
+            options=GameOptions(initial_flips=0),
+        )
+
+        create_args = event_store.create_game.await_args
+        update_args = event_store.update_game_started.await_args
+        created_id = create_args.kwargs.get("game_id", create_args.args[0] if create_args.args else None)
+        updated_id = update_args.args[0] if update_args.args else update_args.kwargs.get("game_id")
+        assert created_id == updated_id
+        assert created_id  # non-empty
+
+    @pytest.mark.asyncio
+    async def test_create_failure_skips_update(self):
+        """If the row never landed, don't try to update a non-existent id."""
+        event_store = MagicMock()
+        event_store.create_game = AsyncMock(side_effect=Exception("db down"))
+        event_store.update_game_started = AsyncMock()
+        logger = GameLogger(event_store)
+
+        await logger.log_game_start_async(
+            room_code="ABCD",
+            num_players=2,
+            num_rounds=1,
+            player_ids=["a", "b"],
+            options=GameOptions(initial_flips=0),
+        )
+
+        event_store.update_game_started.assert_not_awaited()
+        """Only the host ends games — non-host requests are rejected unchanged."""
+        rm = RoomManager()
+        room = rm.create_room()
+        room.add_player("host", "Host", MockWebSocket())
+        room.get_player("host").is_host = True
+        joiner_ws = MockWebSocket()
+        room.add_player("joiner", "Joiner", joiner_ws)
+        room.game_log_id = "game-uuid-untouchable"
+
+        mock_logger = MagicMock()
+        mock_logger.log_game_abandoned = MagicMock()
+
+        ctx = make_ctx(websocket=joiner_ws, player_id="joiner", room=room)
+
         with patch("handlers.get_logger", return_value=mock_logger):
             await handle_end_game(
                 {},