add general file upload support with pool-aware tus client

- add "uploadFile" i18n key (en, zh-CN, zh-TW)
- introduce putFileToPool for tus upload with X-FilePool header
- add ComposeLogic.pickGeneralFile for arbitrary files
- extend uploadAttachment to support poolId override
- add toolbar button for general file upload

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

assets/i18n/zh-TW.json

@@ -122,6 +122,7 @@
     "addVideo": "添加視頻",
     "addPhoto": "添加照片",
     "addFile": "添加文件",
+    "uploadFile": "上傳文件",
     "createDirectMessage": "創建新私人消息",
     "gotoDirectMessage": "前往私信",
     "react": "反應",