v0.2.1 — Follow the focused pane

What's changed

• The context widget now follows the pane you're actually looking at. Active-session
  ranking keys off the last real user turn in the transcript instead of the file's
  mtime, so a backgrounded pane no longer overtakes the focused one.
• tty keystroke focus is trusted only for sessions active within the last 15 minutes,
  so a long-idle session can't be resurrected by a stray tty read.
• The usage and context menu-bar popups now show one at a time.