feat(vector-viz): add news_item support for links and chunk expansion

Add support for news_item document type in the vector visualization page:

- Add "News" checkbox to document type filter options
- Add URL handler to link news items to /apps/news/item/{id}
- Add content fetching for news items in chunk context expansion

This enables users to search and view news articles in the vector
visualization, with clickable links back to Nextcloud News and the
ability to expand chunks to see full article context.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

nextcloud_mcp_server/auth/static/vector-viz.js

@@ -203,6 +203,8 @@ function vizApp() {
                     return `${baseUrl}/apps/contacts`;
                 case 'deck':
                     return `${baseUrl}/apps/deck`;
+                case 'news_item':
+                    return `${baseUrl}/apps/news/item/${result.id}`;
                 default:
                     return `${baseUrl}`;
             }

nextcloud_mcp_server/auth/templates/vector_viz.html

@@ -68,6 +68,10 @@
                                     <input type="checkbox" x-model="docTypes" value="deck" style="margin-right: 4px;">
                                     <span>Deck</span>
                                 </label>
+                                <label style="display: flex; align-items: center; cursor: pointer; font-weight: normal;">
+                                    <input type="checkbox" x-model="docTypes" value="news_item" style="margin-right: 4px;">
+                                    <span>News</span>
+                                </label>
                             </div>
                         </div>