Block pinch and double-tap zoom, including on iOS Safari

iOS Safari ignores user-scalable=no, so zoom is blocked in three layers:
- viewport meta: maximum-scale=1, user-scalable=no on every page
  (covers Android, home-screen apps and iOS focus zoom on inputs)
- CSS: touch-action: pan-x pan-y on html, so scrolling still works but
  pinch and double-tap zoom do not
- JS (fluid.js): cancel Safari's gesture* events and two-finger touchmove

Double-tap is left to CSS rather than JS so rapid repeated taps on
buttons still register as clicks.

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

admin/range.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#f2f2f7">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#000000">
   <meta name="robots" content="noindex, nofollow">

admin/review.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#f2f2f7">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#000000">
   <meta name="robots" content="noindex, nofollow">

public/assets/fluid.js

@@ -524,6 +524,22 @@
     }
   }
 
+  // ---------- 拡大させない ----------
+  // iOS Safari は viewport の user-scalable=no を無視するので、ピンチは gesture* イベントと
+  // 2本指の touchmove を止めて防ぐ。ダブルタップの拡大は CSS の touch-action で止めている
+  // （JS で 2回目のタップを止めると、素早い連打のクリックまで消えてしまうため）
+  const stopZoom = (e) => e.preventDefault();
+  for (const type of ['gesturestart', 'gesturechange', 'gestureend']) {
+    document.addEventListener(type, stopZoom, { passive: false });
+  }
+  document.addEventListener(
+    'touchmove',
+    (e) => {
+      if (e.touches.length > 1) e.preventDefault();
+    },
+    { passive: false },
+  );
+
   window.Fluid = {
     Spring,
     VelocityTracker,

public/assets/style.css

@@ -173,6 +173,8 @@ html {
   -webkit-text-size-adjust: 100%;
   text-size-adjust: 100%;
   background: var(--bg);
+  /* スクロールだけ許し、ピンチとダブルタップの拡大は止める（子の touch-action もこれに絞られる） */
+  touch-action: pan-x pan-y;
 }
 
 body {
@@ -1462,7 +1464,7 @@ body.page-table {
   display: flex;
   flex-direction: column;
   background: var(--room);
-  touch-action: manipulation; /* ダブルタップでの拡大を防ぐ（ピンチ拡大は残す） */
+  touch-action: pan-x pan-y; /* ダブルタップ・ピンチでの拡大を防ぐ */
   -webkit-user-select: none;
   user-select: none;
   -webkit-touch-callout: none;

public/create.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#f2f2f7">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#000000">
   <meta name="robots" content="noindex, nofollow">

public/key.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#f2f2f7">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#000000">
   <meta name="robots" content="noindex, nofollow">

public/lobby.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#f2f2f7">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#000000">
   <meta name="robots" content="noindex, nofollow">

public/table.html

@@ -2,7 +2,7 @@
 <html lang="ja">
 <head>
   <meta charset="utf-8">
-  <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
+  <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover">
   <meta name="theme-color" media="(prefers-color-scheme: light)" content="#eceef1">
   <meta name="theme-color" media="(prefers-color-scheme: dark)" content="#070c0a">
   <meta name="robots" content="noindex, nofollow">