v2.2.4: implement auto_overtime + overtime_unit + notif_before_minutes; remove 3 dead settings

Implemented (previously UI-only with no business effect):
- auto_overtime: when OFF, prompt user on clock-out before banking
- overtime_unit: 15/30/60-min truncation choice now actually applied
- notification_before_minutes: 30-min hardcode -> user-configurable 1~120

Removed dead keys (no readers in business logic):
- auto_detect_boot, notification_enabled, annual_leave_used

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

tests/test_updater.py

@@ -8,7 +8,10 @@ import pytest
 
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from utils.updater_client import _parse_version, is_newer, RELEASES_API
+from utils.updater_client import (
+    _parse_version, is_newer, RELEASES_API,
+    UP_TO_DATE, NETWORK_ERROR, NO_RELEASE, NO_ASSET,
+)
 
 
 class TestVersionParsing:
@@ -59,6 +62,31 @@ class TestApiUrl:
         importlib.reload(updater_client)
 
 
+class TestCheckForUpdate:
+    """check_for_update returns (info, reason) tuple."""
+
+    def test_returns_tuple(self, monkeypatch):
+        # 네트워크 호출이 실패하도록 잘못된 URL
+        monkeypatch.setenv('CLOCKOUT_RELEASES_API', 'http://127.0.0.1:1/nope')
+        import importlib
+        from utils import updater_client
+        importlib.reload(updater_client)
+        try:
+            result = updater_client.check_for_update('1.0.0', timeout=1)
+            assert isinstance(result, tuple) and len(result) == 2
+            info, reason = result
+            assert info is None
+            assert reason == updater_client.NETWORK_ERROR
+        finally:
+            monkeypatch.delenv('CLOCKOUT_RELEASES_API', raising=False)
+            importlib.reload(updater_client)
+
+    def test_constants_distinct(self):
+        # 4개 상수가 모두 서로 다른 값
+        values = {UP_TO_DATE, NETWORK_ERROR, NO_RELEASE, NO_ASSET}
+        assert len(values) == 4
+
+
 class TestUpdaterScript:
     """updater.py 자체 로직."""