data-saving: implement gate with bypass

- Implement DataSavingGate util (previous commit was only the shell)
- Update ProfilePictureWidget to always load avatars via UniversalImage
  using fileId, bypassing CloudFileWidget and its data-saving check
- Keep larger media under data-saving control
- Add i18n strings for data-saving mode

Signed-off-by: Texas0295 <kimura@texas0295.top>

assets/i18n/en-US.json

@@ -350,6 +350,7 @@
   "settingsRealmCompactView": "Compact Realm View",
   "settingsMixedFeed": "Mixed Feed",
   "settingsDataSavingMode": "Data Saving Mode",
+  "dataSavingHint": "Data Saving Mode",
   "settingsAutoTranslate": "Auto Translate",
   "settingsHideBottomNav": "Hide Bottom Navigation",
   "settingsSoundEffects": "Sound Effects",

assets/i18n/zh-CN.json

@@ -316,6 +316,7 @@
   "settingsRealmCompactView": "紧凑领域视图",
   "settingsMixedFeed": "混合动态",
   "settingsDataSavingMode": "流量节省模式",
+  "dataSavingHint": "流量节省模式",
   "settingsAutoTranslate": "自动翻译",
   "settingsHideBottomNav": "隐藏底部导航",
   "settingsSoundEffects": "音效",

assets/i18n/zh-TW.json

@@ -315,7 +315,8 @@
     "settingsRealmCompactView": "緊湊領域視圖",
     "settingsMixedFeed": "混合動態",
     "settingsAutoTranslate": "自動翻譯",
-  "settingsDataSavingMode": "低數據模式",
+    "settingsDataSavingMode": "低數據模式",
+    "dataSavingHint": "低數據模式",
     "settingsHideBottomNav": "隱藏底部導航",
     "settingsSoundEffects": "音效",
     "settingsAprilFoolFeatures": "愚人節功能",