v0.4.0

Added

• Cmd+Option+Up/Down switches between sessions in the viewer without reaching
  for the sidebar — Down moves to the next session in the list, Up the
  previous, wrapping at the ends.
• The viewer notices new releases: a dismissable banner in the sidebar names
  the latest version with a copyable upgrade command (npm install locally,
  redeploy for workers), and the release notes render as a card at the top of
  the stream. Dismissing either hides both until the next release. The check
  lives server-side at /api/version (npm registry + GitHub release notes),
  is cached for six hours, and fails silently — offline costs nothing but the
  absence of the notice.
• The CLI now runs on Windows: session detection walks the process tree with a
  single PowerShell call instead of ps, and sideshow serve --open launches
  the browser via cmd /c start. macOS and Linux are unchanged.