UI polish: live job polling, panel layout, pending button states

- Poll /api/ai-tagging/fields every 2s after any 202 (queued) response in
  ImageLightbox and DoomScrollView so extraction, translation, and description
  results appear automatically without a page refresh
- DoomScrollView extract button now turns accent-coloured while a job is
  queued instead of flashing red; red is reserved for genuine errors
- Kebab menu "Translate" option is now gated on entry.hasExtractedText
  (populated via a batch DB query in the browse API) so it only appears
  when there is text to translate
- Tag panel redesigned: toolbar collapses to just the filename when open;
  panel header holds hide (›), AI Tagger (✨), and Close (✕) buttons;
  sections ordered Description → Text Extraction → Tags; description
  state and generate handler moved from TagSelector into ImageLightbox
- VideoPlayerModal receives the same toolbar/panel restructure
- TagSelector gains hideDescription prop so the parent can own description

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/mixed/MixedView.tsx

@@ -844,7 +844,7 @@ function EntryTile({ entry, onOpen, onTag, onDelete, onRename, onAiTag, onExtrac
                   🔍 Extract Text for Folder
                 </button>
               )}
-              {onTranslate && entry.mediaType === 'image' && (
+              {onTranslate && entry.mediaType === 'image' && entry.hasExtractedText && (
                 <button
                   onClick={(e) => {
                     e.stopPropagation()