refactor(web): ChatView's machine and server-update banners live in useSystemComposerBanners

Reconnect grace, disconnect, version mismatch and server update state only
feed the composer's system banners, so they now sit together in one hook.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
7de6e9a6fcJulius Marminge committed on 10/21/2026, 7:46:49 AMparentc61cf64

Checks

All checks passed
2 files changedLine totals unavailable