Fix chat sliding when the iPhone keyboard opens

Size the shell to the visible area while a field is focused, tuck the bottom bar away, and refit the chat as the keyboard comes and goes.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/style.css

@@ -264,6 +264,14 @@ body { -webkit-touch-callout: none; }
 button, a, .row { -webkit-user-select: none; user-select: none; }
 input, textarea, [contenteditable], .sheet p, .card p, #view .sub { -webkit-user-select: text; user-select: text; }
 
+/* iPhone keyboard (shell.js adds body.kb while a field is focused and the keyboard is up): the shell is exactly the visible area, with no bottom bar in the way */
+@media (max-width: 767px) {
+  body.kb { overflow: hidden; }
+  body.kb #shell { height: var(--vvh, 100dvh); transform: translateY(var(--vvt, 0px)); }
+  body.kb #nav, body.kb #player, body.kb #upd, body.kb #toast { display: none; }
+  body.kb .sgm { min-height: 0; }
+}
+
 /* "A new version is available" notice */
 #upd { position: fixed; left: 50%; transform: translateX(-50%); bottom: calc(var(--nav-h) + var(--sab) + 70px); z-index: 30; display: flex; align-items: center; gap: 12px;
   background: var(--text); color: var(--bg); padding: 8px 8px 8px 16px; border-radius: 14px; box-shadow: 0 6px 24px rgba(0,0,0,.35); max-width: 92vw; }