feat(web): open spaces as a plain chat on phones with a side drawer

Spaces, channels, files, members and the account move into a left drawer,
the top bar keeps only the essentials, and touch devices get a tap menu
instead of always-visible delete buttons. Also fixes the history checkboxes
in the channel settings sheet.

web/src/ui/Icon.tsx

@@ -21,6 +21,8 @@ const PATHS = {
   phone: 'M8 3h8v18H8z M11 18h2',
   tablet: 'M5 4h14v16H5z M11 17h2',
   more: 'M5 12h.01 M12 12h.01 M19 12h.01',
+  menu: 'M4 7h16 M4 12h16 M4 17h16',
+  users: 'M9 11a3 3 0 100-6 3 3 0 000 6z M3 19a6 6 0 0112 0 M16 6a3 3 0 010 6 M18 19a5 5 0 00-3-4.6',
   undo: 'M9 14L4 9l5-5 M4 9h10a6 6 0 010 12h-3',
   warn: 'M12 4l9 16H3z M12 10v4 M12 17h.01',
   sun: 'M12 8a4 4 0 100 8 4 4 0 000-8z M12 2v2 M12 20v2 M2 12h2 M20 12h2 M5 5l1.5 1.5 M17.5 17.5L19 19 M5 19l1.5-1.5 M17.5 6.5L19 5',