gallery: increase server OCR timeout to 20s

- 6s was too short for 13MB DNG upload on mobile
- Bumped to 20s to handle large RAW photos
- Added 'Uploading to server OCR...' status message during upload
- Server OCR handles DNG correctly (tested via curl), so the
  timeout was the root cause of gallery upload failures

static/index.html

@@ -2641,8 +2641,9 @@
           // Try server OCR first (handles more formats like DNG/RAW)
           let ocrData = null;
           try {
+            if (ocrEl) ocrEl.textContent = '⏳ Uploading to server OCR...';
             const controller = new AbortController();
-            const t = setTimeout(() => controller.abort(), 6000);
+            const t = setTimeout(() => controller.abort(), 20000);
             const fd = new FormData();
             fd.append('file', file, file.name || 'sticker.jpg');
             const res = await fetch('/api/ocr', {