feat(ui): adattamento mobile responsive

- Hamburger button (☰) nell'header per aprire sidebar
- Sidebar come drawer overlay su mobile (<768px)
- Sidebar backdrop con chiusura al tap
- Swipe a sinistra per chiudere sidebar
- Safe-area per iPhone notch
- Font-size 16px su input (previene zoom iOS)
- dvh per altezza viewport mobile
- Auto-focus input solo su desktop

src/web/static/index.html

@@ -621,6 +621,103 @@ html, body {
   margin-right: 12px;
 }
 @keyframes spin { to { transform: rotate(360deg); } }
+
+/* Hamburger menu button */
+#btn-menu {
+  display: none;
+  background: none;
+  border: none;
+  color: var(--text-secondary);
+  font-size: 22px;
+  cursor: pointer;
+  padding: 4px 6px;
+  line-height: 1;
+}
+
+/* Sidebar backdrop (mobile) */
+#sidebar-backdrop {
+  display: none;
+  position: fixed;
+  inset: 0;
+  background: rgba(0,0,0,0.5);
+  z-index: 8;
+}
+
+/* ============================================================
+   Mobile Responsive
+   ============================================================ */
+@media (max-width: 768px) {
+  #btn-menu { display: block; }
+
+  #sidebar {
+    position: fixed;
+    left: -320px;
+    top: 0;
+    bottom: 0;
+    width: 300px;
+    min-width: 300px;
+    z-index: 9;
+    transition: left 0.25s ease;
+    box-shadow: 4px 0 20px rgba(0,0,0,0.5);
+  }
+  #sidebar.open { left: 0; }
+  #sidebar-backdrop.open { display: block; }
+
+  #app { flex-direction: column; }
+  #main {
+    width: 100%;
+    height: 100dvh;
+  }
+
+  #header {
+    padding: 0 12px;
+    gap: 10px;
+    min-height: 48px;
+    height: 48px;
+  }
+  #header h1 { font-size: 14px; letter-spacing: 1px; }
+  #header .turn-badge { font-size: 11px; }
+
+  #chat {
+    padding: 12px;
+    gap: 10px;
+    font-size: 15px;
+  }
+
+  #input-area {
+    padding: 8px 10px;
+    padding-bottom: max(8px, env(safe-area-inset-bottom));
+  }
+  #input-area input {
+    font-size: 16px; /* prevent zoom on iOS */
+    padding: 10px 12px;
+  }
+  #btn-send {
+    width: 44px;
+    height: 44px;
+    font-size: 20px;
+  }
+
+  /* Welcome screen */
+  #welcome h1 { font-size: 28px; }
+  #welcome .subtitle { font-size: 14px; }
+  .camp-list { max-width: 100%; padding: 0 12px; }
+  #new-camp-form { width: 100%; max-width: 100%; padding: 0 12px; }
+
+  /* Sidebar content */
+  .sidebar-section { padding: 10px 12px; }
+  .sidebar-section h2 { font-size: 10px; }
+  .char-name { font-size: 14px; }
+  .stat-grid { gap: 3px; }
+  .stat-row { font-size: 12px; }
+  .area-item { font-size: 12px; }
+}
+
+@media (max-width: 480px) {
+  #sidebar { width: 260px; min-width: 260px; left: -260px; }
+  #header h1 { font-size: 12px; }
+  .msg-bubble { font-size: 14px; }
+}
 </style>
 </head>
 <body>
@@ -651,7 +748,7 @@ html, body {
       <div id="area-display"><div class="empty-state">Nessuna area</div></div>
     </div>
     <div class="sidebar-section" id="dm-section">
-      <h2 class="dm-toggle" onclick="toggleDM()">DM ◥</h2>
+      <h2 class="dm-toggle" onclick="toggleDM()">DM +</h2>
       <div id="dm-panel" class="dm-panel hidden">
         <select id="dm-cmd" onchange="onDMCommand()">
           <option value="narrate">Narrate (testo)</option>
@@ -666,10 +763,12 @@ html, body {
       </div>
     </div>
   </div>
+  <div id="sidebar-backdrop" class="hidden" onclick="toggleSidebar()"></div>
 
   <!-- MAIN -->
   <div id="main">
     <div id="header">
+      <button id="btn-menu" onclick="toggleSidebar()">☰</button>
       <div id="conn-indicator" class="conn-status disconnected"></div>
       <h1>Tomba del Mago Guerriero</h1>
       <div class="turn-badge">Turno <span id="turn-counter">0</span></div>
@@ -802,7 +901,7 @@ function connectWS() {
     connIndicator.className = 'conn-status connected';
     input.disabled = false;
     btnSend.disabled = false;
-    input.focus();
+    if (window.innerWidth > 768) input.focus();
     if (reconnectTimer) { clearInterval(reconnectTimer); reconnectTimer = null; }
   };
 
@@ -953,6 +1052,29 @@ function renderAreas(areas) {
   }).join('');
 }
 
+// ================================================================
+// Mobile sidebar
+// ================================================================
+function toggleSidebar() {
+  const sb = document.getElementById('sidebar');
+  const backdrop = document.getElementById('sidebar-backdrop');
+  const open = !sb.classList.contains('open');
+  sb.classList.toggle('open', open);
+  backdrop.classList.toggle('open', open);
+  backdrop.classList.toggle('hidden', !open);
+}
+
+// Close sidebar when swiping left on mobile
+let touchStartX = 0;
+document.addEventListener('touchstart', e => { touchStartX = e.touches[0].clientX; });
+document.addEventListener('touchend', e => {
+  const sb = document.getElementById('sidebar');
+  if (!sb.classList.contains('open')) return;
+  const dx = touchStartX - e.changedTouches[0].clientX;
+  if (dx > 80) toggleSidebar();
+});
+
+
 // ================================================================
 // DM Override
 // ================================================================