fix: PDF extraction bbox compatibility, update date formats, and bump max retries

- Fix bbox format detection in pdf_image_extractor (support Rect and tuple)
- Update date display format to include year (%Y-%m-%d) across templates
- Increase SUMMARY_MAX_RETRIES from 1 to 2 for better error recovery
- Widen date input field for better usability

app/templates/admin_papers.html

@@ -62,7 +62,7 @@
               {{ (paper.title_zh or paper.title_en)[:70] }}{% if (paper.title_zh or paper.title_en)|length > 70 %}...{% endif %}
             </a>
           </td>
-          <td class="time-cell">{{ paper.paper_date.strftime('%m-%d') if paper.paper_date else '-' }}</td>
+          <td class="time-cell">{{ paper.paper_date.strftime('%Y-%m-%d') if paper.paper_date else '-' }}</td>
           <td>{{ paper.upvotes or 0 }}</td>
           <td>
             {% set st = paper_summary_statuses.get(paper.arxiv_id, 'none') %}