support default file pool selection

- add defaultPoolId to AppSettings + persistence
- extend SettingsScreen with pool dropdown
- update uploadAttachment to use defaultPoolId with fallback

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

assets/i18n/en-US.json

@@ -30,6 +30,8 @@
   "fieldEmailAddressMustBeValid": "The email address must be valid.",
   "logout": "Logout",
   "updateYourProfile": "Profile Settings",
+  "settingsDefaultPool": "Default file pool",
+  "settingsDefaultPoolHelper": "Select the default storage pool for file uploads",
   "accountBasicInfo": "Basic Info",
   "accountProfile": "Your Profile",
   "saveChanges": "Save Changes",

assets/i18n/zh-CN.json

@@ -123,6 +123,8 @@
   "addPhoto": "添加照片",
   "addFile": "添加文件",
   "uploadFile": "上传文件",
+  "settingsDefaultPool": "选择文件池",
+  "settingsDefaultPoolHelper": "为文件上传选择一个默认池",
   "createDirectMessage": "创建新私人消息",
   "gotoDirectMessage": "前往私信",
   "react": "反应",

assets/i18n/zh-TW.json

@@ -123,6 +123,9 @@
     "addPhoto": "添加照片",
     "addFile": "添加文件",
     "uploadFile": "上傳文件",
+    "settingsDefaultPool": "選擇文件池",
+    "settingsDefaultPoolHelper": "爲文件上傳選擇一個默認池",
+ 
     "createDirectMessage": "創建新私人消息",
     "gotoDirectMessage": "前往私信",
     "react": "反應",