style: Improve markdown editor styling and functionality

- Update dark mode button icon and styling
- Add styling for new collection button
- Apply default iframe styles in preview pane
- Adjust vertical divider height in header buttons
- Improve handling of JSX-like attributes in markdown
- Add support for new collection functionality
- Refine file loading logic in view mode
- Improve dark mode toggle icon and integration
- Update UI for edit/view mode toggle button

static/js/app.js

@@ -33,9 +33,14 @@ async function autoLoadPageInViewMode() {
 
         // If we found a page to load, load it
         if (pageToLoad) {
-            await editor.loadFile(pageToLoad);
-            // Highlight the file in the tree and expand parent directories
-            fileTree.selectAndExpandPath(pageToLoad);
+            // Use fileTree.onFileSelect to handle both text and binary files
+            if (fileTree.onFileSelect) {
+                fileTree.onFileSelect({ path: pageToLoad, isDirectory: false });
+            } else {
+                // Fallback to direct loading (for text files only)
+                await editor.loadFile(pageToLoad);
+                fileTree.selectAndExpandPath(pageToLoad);
+            }
         } else {
             // No files found, show empty state message
             editor.previewElement.innerHTML = `
@@ -397,6 +402,9 @@ document.addEventListener('DOMContentLoaded', async () => {
                 // Highlight the file in the tree
                 fileTree.selectAndExpandPath(item.path);
 
+                // Save as last viewed page (for binary files too)
+                editor.saveLastViewedPage(item.path);
+
                 // Update URL to reflect current file
                 updateURL(currentCollection, item.path, isEditMode);