1.1.1

1.1.1: @ mentions, keyboard approvals, find, and a resizable sidebar

- @ in the composer lists the files and folders of the session's folder
  (from git when it is a repository) and inserts the one picked.
- Approvals: a waiting edit, write or command shows what it would do, and
  Alt+Y / Alt+A / Alt+N answer the oldest one.
- Shortcuts: Ctrl+F finds in the conversation, Ctrl+Tab moves between
  sessions, Ctrl+K searches them, Ctrl+/ lists every shortcut.
- A search box above the session list.
- The sidebar can be dragged wider or narrower, or sized with the arrow
  keys on its edge; a double-click puts it back.
- The window opens where it was, on the session that was open.
- Recent folders in the folder menu; a folder dropped on the window, or
  named when the app starts, starts a session there.
- The top bar says what the session has cost; each answer can be copied
  as Markdown, and a session exported as a .md file.
- Background commands: watch the output as it comes, and open a dev server
  once it prints its local address.
- The taskbar shows when a run goes and when one waits for approval.
- Fix: closing the window after computer use left the app running with no
  window, and every later start of the app did nothing.
- New sessions start on the account's default model.