Fix proxy settings modal never saving — wrong third arg to Nova.modal

Nova.modal(title, bodyHtml, footerHtml) expects footerHtml as an HTML
string, but an async callback was passed instead. The function got
stringified as garbage text in the footer with no save button, so
nothing ever saved regardless of mode chosen.

Replaced with proper footer HTML (Cancel + Save buttons) and wired the
save logic as an event listener on the save button.

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

panel/public/assets/js/admin.js

@@ -3054,7 +3054,13 @@ window.proxySettings = async () => {
         <span id="ps-test-result" style="margin-left:0.75rem;font-size:0.85rem"></span>
       </div>
     </div>
-  `, async () => {
+  `,
+  `<button class="btn btn-ghost" onclick="this.closest('.modal-overlay').remove()">Cancel</button>
+   <button class="btn btn-primary" id="ps-save-btn">Save Settings</button>`
+  );
+  ov.querySelector('#ps-save-btn').addEventListener('click', async () => {
+    const btn  = ov.querySelector('#ps-save-btn');
+    btn.disabled = true; btn.textContent = 'Saving…';
     const mode = document.getElementById('ps-mode')?.value;
     const pass = document.getElementById('ps-pass')?.value;
     const body = {
@@ -3066,7 +3072,8 @@ window.proxySettings = async () => {
     };
     const r = await Nova.api('proxy', 'settings', { method: 'POST', body });
     Nova.toast(r?.success ? 'Settings saved' : (r?.message || 'Failed'), r?.success ? 'success' : 'error');
-    if (r?.success) Nova.loadPage('nginx-proxy', window._novaPages);
+    if (r?.success) { ov.remove(); Nova.loadPage('nginx-proxy', window._novaPages); }
+    else { btn.disabled = false; btn.textContent = 'Save Settings'; }
   });
 };