feat(checkpoints): add Enrich HF Metadata (AI) to card context menu

The option only existed in the LoRA page menu. Move updateEnrichMenuItem
and enrichWithAgent into ModelContextMenuMixin so both pages share the
implementation, and add the menu item to the checkpoints template.

templates/checkpoints.html

@@ -25,6 +25,9 @@
             </div>
         </div>
     </div>
+    <div class="context-menu-item" data-action="enrich-hf-llm">
+        <i class="fas fa-wand-magic-sparkles"></i> <span>{{ t('loras.contextMenu.enrichHfAgent') }}</span>
+    </div>
     <div class="context-menu-separator menu-section-break"></div>
     <!-- Workflow -->
     <div class="context-menu-item" data-action="copyname"><i class="fas fa-copy"></i> {{ t('loras.contextMenu.copyFilename') }}</div>