🔒 Add privacy settings for leaderboard visibility

✨ Features:
- Added show_in_leaderboard column to players table (default: false)
- Replaced Quick Actions with Settings section in dashboard
- Added toggle switch for leaderboard visibility
- Created settings modal with privacy controls

🔧 API Changes:
- Added /api/v1/private/update-player-settings endpoint
- Updated best-times queries to filter by show_in_leaderboard
- Updated times-with-details to respect privacy settings
- Added updated_at column to players table

🎨 UI/UX:
- Modern toggle switch design
- Responsive settings modal
- Success/error notifications
- Clear privacy explanation

🔐 Privacy:
- Default: Times are NOT shown in global leaderboard
- Users can opt-in via settings
- Personal dashboard always shows own times
- Global leaderboard only shows opted-in users

public/js/dashboard.js

@@ -941,6 +941,105 @@ setInterval(() => {
     checkAchievementNotifications();
 }, 30000);
 
+// Settings Functions
+function showSettings() {
+    const modal = document.getElementById('settingsModal');
+    if (modal) {
+        modal.style.display = 'block';
+        loadSettings();
+    }
+}
+
+async function loadSettings() {
+    try {
+        if (!currentPlayerId) {
+            console.error('No player ID available');
+            return;
+        }
+        
+        // Load current player settings
+        const response = await fetch(`/api/v1/public/user-player/${currentUser.id}`);
+        const result = await response.json();
+        
+        if (result.success && result.data) {
+            const showInLeaderboard = result.data.show_in_leaderboard || false;
+            document.getElementById('showInLeaderboard').checked = showInLeaderboard;
+        }
+    } catch (error) {
+        console.error('Error loading settings:', error);
+    }
+}
+
+function updateLeaderboardSetting() {
+    const checkbox = document.getElementById('showInLeaderboard');
+    console.log('Leaderboard setting changed:', checkbox.checked);
+}
+
+async function saveSettings() {
+    try {
+        if (!currentPlayerId) {
+            console.error('No player ID available');
+            return;
+        }
+        
+        const showInLeaderboard = document.getElementById('showInLeaderboard').checked;
+        
+        // Update player settings
+        const response = await fetch(`/api/v1/private/update-player-settings`, {
+            method: 'POST',
+            headers: {
+                'Content-Type': 'application/json',
+                'Authorization': `Bearer ${localStorage.getItem('apiKey')}`
+            },
+            body: JSON.stringify({
+                player_id: currentPlayerId,
+                show_in_leaderboard: showInLeaderboard
+            })
+        });
+        
+        const result = await response.json();
+        
+        if (result.success) {
+            showNotification('Einstellungen erfolgreich gespeichert!', 'success');
+            closeModal('settingsModal');
+        } else {
+            showNotification('Fehler beim Speichern der Einstellungen: ' + result.message, 'error');
+        }
+    } catch (error) {
+        console.error('Error saving settings:', error);
+        showNotification('Fehler beim Speichern der Einstellungen', 'error');
+    }
+}
+
+function showNotification(message, type = 'info') {
+    // Create notification element
+    const notification = document.createElement('div');
+    notification.className = `notification notification-${type}`;
+    notification.style.cssText = `
+        position: fixed;
+        top: 20px;
+        right: 20px;
+        background: ${type === 'success' ? '#10b981' : type === 'error' ? '#ef4444' : '#3b82f6'};
+        color: white;
+        padding: 1rem 1.5rem;
+        border-radius: 0.5rem;
+        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
+        z-index: 10000;
+        max-width: 300px;
+        font-weight: 500;
+    `;
+    notification.textContent = message;
+    
+    document.body.appendChild(notification);
+    
+    // Remove notification after 3 seconds
+    setTimeout(() => {
+        if (notification.parentNode) {
+            notification.parentNode.removeChild(notification);
+        }
+    }, 3000);
+}
+
 document.addEventListener('DOMContentLoaded', function() {
     // Add cookie settings button functionality
     const cookieSettingsBtn = document.getElementById('cookie-settings-footer');