Frontend: hamburger menu v hlavicke na mobile

Hlavicka GameListu sa na uzkych displejoch nezmestila do jedneho
riadku. Pod sm: breakpointom sa polozky zbalia do dropdownu.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/HeaderMenu.tsx

@@ -0,0 +1,100 @@
+import { useEffect, useRef, useState } from 'react';
+
+interface Props {
+  username?: string;
+  onHistory: () => void;
+  onDonate: () => void;
+  onLogout: () => void;
+}
+
+/** Header navigation: a row of links from `sm:` up, a hamburger dropdown below it. */
+export default function HeaderMenu({ username, onHistory, onDonate, onLogout }: Props) {
+  const [open, setOpen] = useState(false);
+  const ref = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    if (!open) return;
+    const onPointerDown = (e: PointerEvent) => {
+      if (!ref.current?.contains(e.target as Node)) setOpen(false);
+    };
+    const onKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'Escape') setOpen(false);
+    };
+    document.addEventListener('pointerdown', onPointerDown);
+    document.addEventListener('keydown', onKeyDown);
+    return () => {
+      document.removeEventListener('pointerdown', onPointerDown);
+      document.removeEventListener('keydown', onKeyDown);
+    };
+  }, [open]);
+
+  const pick = (action: () => void) => () => {
+    setOpen(false);
+    action();
+  };
+
+  return (
+    <>
+      <div className="hidden sm:flex items-center gap-3 text-sm">
+        <span className="text-green-dim">{username}</span>
+        <button onClick={onHistory} className="text-gold hover:text-gold-bright">
+          História
+        </button>
+        <button onClick={onDonate} className="text-gold hover:text-gold-bright">
+          Na kávu
+        </button>
+        <button onClick={onLogout} className="text-green-dim hover:text-gold">
+          Odhlásiť
+        </button>
+      </div>
+
+      <div ref={ref} className="relative sm:hidden">
+        <button
+          onClick={() => setOpen((o) => !o)}
+          aria-label="Menu"
+          aria-expanded={open}
+          aria-haspopup="menu"
+          className="flex flex-col justify-center gap-[5px] w-9 h-9 items-center rounded-lg border border-gold/20 text-gold hover:border-gold/50 transition-colors"
+        >
+          <span className="block w-4 h-px bg-current" />
+          <span className="block w-4 h-px bg-current" />
+          <span className="block w-4 h-px bg-current" />
+        </button>
+
+        {open && (
+          <div
+            role="menu"
+            className="absolute right-0 top-11 z-40 w-44 bg-header border border-[#142018] rounded-xl py-1 shadow-[0_20px_60px_rgba(0,0,0,.6)]"
+          >
+            {username && (
+              <p className="px-4 py-2 text-xs text-green-dim border-b border-[#142018] truncate">
+                {username}
+              </p>
+            )}
+            <button
+              role="menuitem"
+              onClick={pick(onHistory)}
+              className="block w-full text-left px-4 py-2.5 text-sm text-gold hover:bg-gold/10"
+            >
+              História
+            </button>
+            <button
+              role="menuitem"
+              onClick={pick(onDonate)}
+              className="block w-full text-left px-4 py-2.5 text-sm text-gold hover:bg-gold/10"
+            >
+              Na kávu
+            </button>
+            <button
+              role="menuitem"
+              onClick={pick(onLogout)}
+              className="block w-full text-left px-4 py-2.5 text-sm text-green-dim hover:bg-gold/10 hover:text-gold"
+            >
+              Odhlásiť
+            </button>
+          </div>
+        )}
+      </div>
+    </>
+  );
+}

frontend/src/pages/GameList.tsx

@@ -3,6 +3,7 @@ import { useNavigate } from 'react-router-dom';
 import { useGameStore } from '../store/gameStore';
 import { emit, socket, setAuthToken } from '../lib/socket';
 import { trackEvent } from '../lib/track';
+import HeaderMenu from '../components/HeaderMenu';
 import NameModal from '../components/NameModal';
 import RulesModal from '../components/RulesModal';
 
@@ -33,18 +34,12 @@ export default function GameList() {
     <div className="max-w-md mx-auto p-4 pt-8 min-h-screen">
       <div className="flex items-center justify-between mb-6">
         <h1 className="font-serif text-2xl text-gold tracking-wide">Bridžik</h1>
-        <div className="flex items-center gap-3 text-sm">
-          <span className="text-green-dim">{account?.username}</span>
-          <button onClick={() => navigate('/history')} className="text-gold hover:text-gold-bright">
-            História
-          </button>
-          <button onClick={() => navigate('/donate')} className="text-gold hover:text-gold-bright">
-            Na kávu
-          </button>
-          <button onClick={handleLogout} className="text-green-dim hover:text-gold">
-            Odhlásiť
-          </button>
-        </div>
+        <HeaderMenu
+          username={account?.username}
+          onHistory={() => navigate('/history')}
+          onDonate={() => navigate('/donate')}
+          onLogout={handleLogout}
+        />
       </div>
 
       <div className="flex flex-col gap-3 mb-6">