Revise transition update message in header

Updated announcement banner to reflect changes in service availability and support for users.

Author: mkutmon

_includes/header.html

@@ -50,10 +50,8 @@
   </div>
   <!-- ANNOUNCEMENT BANNER -->
 <div style="background-color: #fff3cd; color: #333; text-align: center; padding: 10px 20px; font-size: small; border-bottom: 1px solid #f0ad4e;">
-  ⚠️ <strong>Transition update:</strong>
-  As announced, the Classic WikiPathways site is now <strong>read-only</strong> and the old web service has been turned off.<br/>
-  <strong>From 1 May 2026, the Classic site will be fully retired</strong> and we will complete our transition to the new GitHub-based system.<br/>
-  <strong>Webservice users:</strong> If you are still using the old web service, please <a href="https://github.com/wikipathways/wikipathways-help/discussions" style="color: #333; text-decoration: underline;"><strong>contact us immediately</strong></a> so we can help you transition.<br/>
-  <strong>Curators:</strong> PathVisio upload is currently not working. If you need to upload or update a pathway, please <a href="https://github.com/wikipathways/wikipathways-help/discussions" style="color: #333; text-decoration: underline;">reach out</a> and we will help you find a solution. This should be resolved in the next few weeks.
-</div>
+  ⚠️ <strong>Transition update:</strong><br/>
+  As announced, the Classic WikiPathways site is now <strong>read-only</strong> and the old web service has been turned off. <strong>From 1 May 2026, the Classic site will be fully retired</strong> and we will complete our transition to the new GitHub-based system.<br/>
+  <strong>Webservice users:</strong> If you are still using the old web service, please <a href="https://github.com/wikipathways/wikipathways-help/discussions" style="color: #333; text-decoration: underline;">contact us immediately</a> so we can help you transition.<br/>
+  <strong>Curators:</strong> PathVisio upload is temporarily unavailable. Please <a href="https://github.com/wikipathways/wikipathways-help/discussions" style="color: #333; text-decoration: underline;">reach out</a> if you need to upload or update a pathway.
 </header>