Add auto-upgrade buildings feature with middle mouse click (#1597)

## Description:

This PR implements a new feature allowing automatic upgrade of the
nearest building using the middle mouse button. This feature greatly
simplifies the upgrade process that previously required a right-click +
building recreation.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I have read and accepted the CLA agreement (only required once).

## Please put your Discord username so you can be contacted if a bug or
regression is found:

Kipstzz

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>

src/client/HelpModal.ts

@@ -138,6 +138,14 @@ export class HelpModal extends LitElement {
                 </td>
                 <td>${translateText("help_modal.action_reset_gfx")}</td>
               </tr>
+              <tr>
+                <td>
+                  <div class="mouse-shell">
+                    <div class="mouse-wheel" id="highlighted-wheel"></div>
+                  </div>
+                </td>
+                <td>${translateText("help_modal.action_auto_upgrade")}</td>
+              </tr>
             </tbody>
           </table>
         </div>