fix: Workshop mobile layout + navigation from all modes

Mobile:
- Workshop nav tabs full-width, hide logo, hide hero header
- Search/sort/share go full-width stacked
- Tags scroll horizontally
- Share button large and prominent
- Patch cards single column, shorter previews
- Auth modal fits mobile viewport

Navigation:
- Workshop button in Sandbox hamburger menu (mobile)
- Workshop tab in WorldMap mobile tab bar
- GameApp passes onWorkshop prop through to WorldMap

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

packages/client/src/game/GameApp.jsx

@@ -17,7 +17,7 @@ import { WORLD_12 } from './levels/world12.js';
 
 const allWorlds = [WORLD_1, WORLD_2, WORLD_3, WORLD_4, WORLD_5, WORLD_6, WORLD_7, WORLD_8, WORLD_9, WORLD_10, WORLD_11, WORLD_12];
 
-export default function GameApp({ onSwitchToSandbox }) {
+export default function GameApp({ onSwitchToSandbox, onSwitchToWorkshop }) {
   const [view, setView] = useState('map');
   const [currentLevel, setCurrentLevel] = useState(null);
   const [currentLevelIndex, setCurrentLevelIndex] = useState(0);
@@ -78,6 +78,7 @@ export default function GameApp({ onSwitchToSandbox }) {
       <WorldMap
         onSelectLevel={handleSelectLevel}
         onSandbox={onSwitchToSandbox}
+        onWorkshop={onSwitchToWorkshop}
         onAdmin={() => setShowAdmin(true)}
       />
       {showAdmin && (

packages/client/src/game/WorldMap.jsx

@@ -45,10 +45,11 @@ function isWorldUnlocked(world) {
 const MOBILE_TABS = [
   { id: 'game', label: 'JUEGO', icon: '🎮' },
   { id: 'sandbox', label: 'SANDBOX', icon: '🎛' },
+  { id: 'workshop', label: 'WORKSHOP', icon: '🎵' },
   { id: 'config', label: 'CONFIG', icon: '⚙' },
 ];
 
-export default function WorldMap({ onSelectLevel, onSandbox, onAdmin }) {
+export default function WorldMap({ onSelectLevel, onSandbox, onAdmin, onWorkshop }) {
   const totalStars = getTotalStars();
   const maxStars = getMaxStars();
   const [search, setSearch] = useState('');
@@ -236,6 +237,7 @@ export default function WorldMap({ onSelectLevel, onSandbox, onAdmin }) {
           activeTab="game"
           onTabChange={(id) => {
             if (id === 'sandbox') onSandbox?.();
+            if (id === 'workshop') onWorkshop?.();
             if (id === 'config') onAdmin?.();
           }}
         />