feat: load and save user-selected preview fit mode in settings

src/js/app.js

@@ -104,6 +104,10 @@ document.addEventListener('DOMContentLoaded', function () {
         // Initial render
         renderVisualization();
 
+        // Load saved preview fit mode from settings
+        const savedPreviewFitMode = getSetting('ui.previewFitMode') || 'default';
+        setPreviewFitMode(savedPreviewFitMode);
+
         // Initialize auto-save functionality
         initializeAutoSave();
 

src/js/editor.js

@@ -173,6 +173,11 @@ function setPreviewFitMode(mode) {
     document.getElementById('preview-fit-width').classList.toggle('active', mode === 'width');
     document.getElementById('preview-fit-full').classList.toggle('active', mode === 'full');
 
+    // Save to settings
+    if (typeof updateSetting === 'function') {
+        updateSetting('ui.previewFitMode', mode);
+    }
+
     // Re-render with new fit mode
     renderVisualization();
 }

src/js/user-settings.js

@@ -20,7 +20,8 @@ const DEFAULT_SETTINGS = {
     },
 
     ui: {
-        theme: 'light'             // 'light' | 'experimental'
+        theme: 'light',            // 'light' | 'experimental'
+        previewFitMode: 'default'  // 'default' | 'width' | 'full'
     },
 
     formatting: {