fix(offline): hotseat form — natural scroll + focus-into-view (keyboard)

The nested scroll region regressed the keyboard behaviour (a double
scroll: the whole screen scrolled with a huge blank area under the Start
button, and a focused bottom row hid behind the keyboard). Drop it: the
hotseat form now flows naturally and scrolls with the screen's own scroll
(.page.scrollform: no forced full height, no pinned button), and a name
input scrolls itself into view (centred above the keyboard) on focus.

ui/src/screens/NewGame.svelte

@@ -232,6 +232,14 @@
     deleteRow = null;
   }
 
+  // Centre a focused name input above the soft keyboard: the keyboard shrinks the screen (--vvh),
+  // so wait a beat for it to open + the layout to settle, then scroll the field into view (the
+  // default focus-scroll leaves a bottom row hidden behind the keyboard).
+  function bringIntoView(e: FocusEvent): void {
+    const el = e.currentTarget as HTMLElement;
+    setTimeout(() => el.scrollIntoView({ block: 'center' }), 300);
+  }
+
   function setHostPlays(yes: boolean): void {
     askHostPlays = false;
     if (!yes) return;
@@ -278,7 +286,10 @@
 </script>
 
 <Screen title={t('new.title')} back="/">
-  <div class="page">
+  <!-- The hotseat form flows naturally and scrolls with the screen's own scroll (scrollform: no
+       forced full height, no pinned button) so a focused name input's soft keyboard just scrolls the
+       page rather than fighting a nested scroll region. -->
+  <div class="page" class:scrollform={mode === 'friends' && offlineMode.active}>
       <!-- The auto/friends selector. Online it is hidden for guests (no friends to invite). Offline
            it is always shown: "quick" is the local vs_ai flow, "with friends" is the local
            pass-and-play (hotseat) flow. -->
@@ -332,11 +343,7 @@
         >{t('new.start')}</button>
       {:else if offlineMode.active}
         <!-- Offline pass-and-play (hotseat): a device-local 2-4 human game. The host sets a master
-             PIN first (it gates the roster); each seat may add its own PIN. The scrollable region +
-             the pinned Start button mirror the friends form, so a name input's soft keyboard shrinks
-             the region (no full-height spacer that would paint a blank block behind the keyboard). -->
-        <div class="fg">
-          <div class="hs-scroll">
+             PIN first (it gates the roster); each seat may add its own PIN. -->
         <div class="hostpin">
           <span class="ftitle">{t('hotseat.hostPin')}</span>
           <button class="plink" onclick={() => (pad = hostPin ? { kind: 'host-change' } : { kind: 'host-set' })}>
@@ -375,6 +382,7 @@
                 disabled={!hostPin}
                 placeholder={t('hotseat.playerName')}
                 maxlength="40"
+                onfocus={bringIntoView}
                 oninput={() => (row.committed = commitName(row.name, row.committed))}
                 onblur={() => (row.name = row.committed)}
               />
@@ -401,13 +409,11 @@
             + {t('hotseat.addPlayer')}
           </button>
         {/if}
-          </div>
         <button
           class="invite"
           disabled={!hostPin || !inviteVariant || !rosterReady(rows) || starting}
           onclick={startHotseat}
         >{t('new.start')}</button>
-        </div>
       {:else if friends.length === 0}
         <p class="subtitle">{t('new.noFriends')}</p>
       {:else}
@@ -486,6 +492,12 @@
     height: 100%;
     box-sizing: border-box;
   }
+  /* The hotseat form: natural height (grows past the viewport → the screen's own scroll takes over)
+     with no full-height pinning, so a focused name input just scrolls the page above the keyboard. */
+  .page.scrollform {
+    height: auto;
+    min-height: 100%;
+  }
   .subtitle {
     color: var(--text-muted);
     margin: 0;
@@ -680,17 +692,6 @@
     line-height: 1.4;
   }
   /* --- offline hotseat roster --- */
-  /* The scrollable region (host PIN + variants + roster), pinned above the Start button — mirrors
-     the friends form so a focused name input's soft keyboard shrinks this region (via --vvh on the
-     screen) instead of leaving a full-height blank spacer painted behind the keyboard. */
-  .hs-scroll {
-    flex: 1;
-    min-height: 0;
-    overflow-y: auto;
-    display: flex;
-    flex-direction: column;
-    gap: 14px;
-  }
   .hostpin {
     display: flex;
     align-items: center;