fix: store menu 404, logger crash, platform detection, and sidebar UX

- Fix store menu API URL (/store/menu/render/store, not /store/core/...)
- Fix storeLog/merchantLog fallback to console object instead of console.log
- Embed platform_id/platform_code in store JWT from URL context at login
- Use token_platform_id in store menu endpoint with DB fallback for old tokens
- Add "Menu unavailable" warning in sidebar fallback for all three frontends
- Standardize admin section default to all-open (consistent with store/merchant)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/templates/admin/partials/sidebar.html

@@ -88,7 +88,11 @@
                 </a>
             </li>
         </ul>
-        <p class="px-6 py-3 text-xs text-gray-400">Loading menu...</p>
+        <div class="px-6 mt-4">
+            <p class="text-xs text-gray-400 dark:text-gray-500">
+                Menu unavailable. Showing default items only.
+            </p>
+        </div>
     </div>
 </div>
 {% endmacro %}