[httpsphl]

What

Follow-ups to the unread replies in the sidebar (#107):

• Mark as unread: a new item in a bot's menu (sidebar right-click and the header's "more" menu). On an unread bot it reads "Mark as read".
  • The mark is kept in botloft.unread until the chat is opened.
  • Marking the open chat closes it and goes back to the crew's page.
• Count per crew: an accent pill beside each crew's name shows how many of its bots are unread, with screen reader text ("2 unread").
• Mark on the taskbar icon: a new setting in Settings > Notifications, "Mark the icon when a bot replies", on by default. While a bot is unread, the taskbar icon shows the same dot it shows when something waits for the owner. The setting only appears on Windows, the only system with that mark.
• Refactor: the seen/unread state and its actions move to store/seen.ts, so store/app.ts is shorter than it was on main.
• Spec 15.1 and 15.2 are updated.

Checks

• pnpm check: 272 tests pass. unread.test.tsx adds two tests:
  • marking a bot unread and read from the menu, the crew count, and marking the open chat;
  • the icon mark following unread bots and the setting.
• The bot menu test now lists the new item.
• Preview (pt-BR): "Marcar como não lida" on a bot marks its row, and the crew pill shows the count.

Nothing depends on the real Claude Code.