Deterministically cover the SteamAPIError branch in stats refresh

The `except SteamAPIError` branch in _refresh_recently_played_completions
was only covered incidentally, by cmd_stats tests that make a real
network call which fails — reachable only under certain pytest-randomly
orderings, so CI's 100% coverage gate flaked (missing _stats.py 368-370).

Add a focused test that mocks SteamAPIClient.get_owned_games to raise
SteamAPIError, covering the branch reliably regardless of order or
network.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017RRCdR4D8SaVrN2xraMQxM

steam_backlog_enforcer/tests/test_stats.py

@@ -21,7 +21,7 @@ from steam_backlog_enforcer._stats import (
 from steam_backlog_enforcer._web_dataset import PaceVsHLTB
 from steam_backlog_enforcer.config import Config, State
 from steam_backlog_enforcer.protondb import ProtonDBRating
-from steam_backlog_enforcer.steam_api import GameInfo
+from steam_backlog_enforcer.steam_api import GameInfo, SteamAPIError
 
 _PKG = "steam_backlog_enforcer._stats"
 
@@ -990,6 +990,24 @@ class TestRefreshRecentlyPlayedCompletions:
             result = _refresh_recently_played_completions(games, Config())
         assert result == games
 
+    def test_steam_api_error_returns_games_unchanged(self) -> None:
+        """A SteamAPIError while fetching owned games is swallowed."""
+        games = [GameInfo(1, "G", 10, 0, 60)]
+        with (
+            patch(f"{_PKG}.SNAPSHOT_FILE") as mock_sf,
+            patch(f"{_PKG}.SteamAPIClient") as mock_cls,
+        ):
+            mock_sf.stat.return_value.st_mtime = 1_000_000.0
+            mock_cls.return_value.get_owned_games.side_effect = SteamAPIError(
+                "api down"
+            )
+            from steam_backlog_enforcer._stats import (
+                _refresh_recently_played_completions,
+            )
+
+            result = _refresh_recently_played_completions(games, Config())
+        assert result == games
+
     def test_no_recently_played_returns_games_unchanged(self) -> None:
         games = [GameInfo(1, "G", 10, 0, 60)]
         with (