fix: polish explorer, error states and page alignment

- Explorer: 13px code, page-coloured dark editor, padded Markdown with a
  readable width, full repository ID on hover, sidebar footer kept clear
  of the floating Ko-fi button.
- Explorer errors render as a card with links home and to the FAQ; the
  empty action bar and Raw/Download buttons are hidden.
- Unknown error codes show the generic message instead of the raw
  ERRORS.<code> key.
- All app pages share one content column; New anonymization starts at
  the top instead of floating mid-screen.
- Status page: spaced action buttons, aligned status pill, no second
  Ko-fi embed under the support cards.
- Claim placeholders; consistent notebook option on new conferences.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

public/partials/status.htm

@@ -1,6 +1,6 @@
 <div class="container paper-page status-page">
   <div class="paper-crumbs">Anonymization &nbsp;/&nbsp; <span class="here">Status</span></div>
-  <div class="d-flex align-items-end justify-content-between flex-wrap" style="gap: 12px;">
+  <div class="d-flex align-items-center justify-content-between flex-wrap" style="gap: 12px;">
     <div>
       <h1 class="paper-page-title">Status of <em>{{ repoId }}</em></h1>
       <p class="paper-page-lede">Track progress as your anonymization is prepared.</p>
@@ -106,9 +106,5 @@
         <span class="paper-support-cta">GitHub Sponsors <svg class="ui-icon" aria-hidden="true"><use href="#ui-icon-arrow-right"></use></svg></span>
       </a>
     </div>
-
-    <div class="paper-kofi-wrap">
-      <iframe id="kofiframe" src="https://ko-fi.com/tdurieux/?hidefeed=true&amp;widget=true&amp;embed=true&amp;preview=true" title="tdurieux" loading="lazy"></iframe>
-    </div>
   </section>
 </div>