Fix multi-plate thumbnail display in queue and add archive plate browsing

- Queue now shows correct plate thumbnail based on selected plate_id
  (previously always showed plate 1 regardless of selection)
- Archive cards now support plate browsing for multi-plate 3MF files:
  - Left/right arrows to cycle through plates on hover
  - Dot indicators at bottom show current plate (clickable)
  - Lazy-loads plate data only when user hovers
- Added getArchivePlateThumbnail and getLibraryFilePlateThumbnail API methods

Closes #166

static/index.html

@@ -23,8 +23,8 @@
 
     <!-- Splash screens for iOS -->
     <link rel="apple-touch-startup-image" href="/img/android-chrome-512x512.png" />
-    <script type="module" crossorigin src="/assets/index-DuO_7tQ3.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-nwJjDqT-.css">
+    <script type="module" crossorigin src="/assets/index-abyjQYWw.js"></script>
+    <link rel="stylesheet" crossorigin href="/assets/index-DFuUL8IF.css">
   </head>
   <body>
     <div id="root"></div>