v1.9.1: fix world map rendering and resolve eight small TODO items

World map:
- Fix zero-padded ISO numeric ids leaving 31 countries unrendered
  (Brazil, Australia, Belgium, Austria, Algeria and more)
- Fix Russia and Fiji smearing across the full map width at the antimeridian
  by unwrapping ring longitudes and drawing them at both edges
- Crop to 84N-60S, add evenodd fill rule, 174 countries rendered

Improvements:
- Logger::tail() reads backwards in chunks instead of loading the whole file
- External links get rel=noopener noreferrer in footer and Markdown content
- formatDisplayName() cleaned up and guarded against empty input
- Export statistics as CSV (Excel BOM) or JSON
- GeoIP database auto-updates when older than 35 days
- Editor shortcuts Ctrl/Cmd+S to save and Ctrl/Cmd+N for a new page
- Live search filter in the admin content browser
- Content versioning with timestamped .bak copies in content/-backups/

Also removes eight stale TODO entries that were already implemented

admin/templates/pages/content-edit.php

@@ -45,7 +45,7 @@
             </div>
             <?php endif; ?>
             <div class="d-flex gap-2 mt-3">
-                <button type="submit" class="btn btn-primary">
+                <button type="submit" class="btn btn-primary" title="Opslaan (Ctrl+S)">
                     <i class="bi bi-check-lg"></i> Opslaan
                 </button>
                 <?php if ($isEditable): ?>