Release version 0.15.9

• feat(sidebar): Open Folder and Clone Repository are now one hover away on the Folders header.
• fix(tabs): Quitting with only an unsent draft open no longer reopens to a blank, unusable screen.
• fix(chat): Empty scratch folders left by unsent or deleted chats are now cleaned up at startup.

发布版本 0.15.9

• 功能(侧边栏)：「打开文件夹」和「克隆仓库」现在悬停「文件夹」标题栏即可触达。
• 修复(标签页)：仅打开未发送草稿时退出，重新打开不再停在空白且无法操作的界面。
• 修复(聊天)：未发送或已删除聊天残留的空临时目录，现在会在启动时自动清理。