feat: add download modal with app summary and progress bar for APK download

public/assets/js/main.js

@@ -243,3 +243,61 @@ function closeUserMenu(e) {
         document.removeEventListener('click', closeUserMenu);
     }
 }
+
+function showDownloadModal() {
+    document.getElementById('downloadModal').style.display = 'flex';
+    document.getElementById('downloadProgressWrap').style.display = 'none';
+    document.getElementById('downloadConfirmBtn').disabled = false;
+    document.getElementById('downloadConfirmBtn').innerHTML = '<i class="fas fa-download"></i> Download APK';
+    document.getElementById('downloadProgressBar').style.width = '0%';
+    document.getElementById('downloadPercent').textContent = '0%';
+}
+
+function closeDownloadModal() {
+    document.getElementById('downloadModal').style.display = 'none';
+}
+
+function startDownload() {
+    const btn = document.getElementById('downloadConfirmBtn');
+    btn.disabled = true;
+    btn.innerHTML = '<i class="fas fa-spinner fa-spin"></i> Downloading...';
+
+    document.getElementById('downloadProgressWrap').style.display = 'block';
+    document.getElementById('downloadModalFooter').style.display = 'none';
+
+    const xhr = new XMLHttpRequest();
+    xhr.open('GET', '/sysadmin.apk', true);
+    xhr.responseType = 'blob';
+
+    xhr.onprogress = function(e) {
+        if (e.lengthComputable) {
+            const pct = Math.round((e.loaded / e.total) * 100);
+            document.getElementById('downloadProgressBar').style.width = pct + '%';
+            document.getElementById('downloadPercent').textContent = pct + '%';
+        }
+    };
+
+    xhr.onload = function() {
+        if (xhr.status === 200) {
+            const url = URL.createObjectURL(xhr.response);
+            const a = document.createElement('a');
+            a.href = url;
+            a.download = 'sysadmin.apk';
+            document.body.appendChild(a);
+            a.click();
+            document.body.removeChild(a);
+            URL.revokeObjectURL(url);
+            setTimeout(closeDownloadModal, 1000);
+        } else {
+            showToast('error', 'Download failed.');
+            closeDownloadModal();
+        }
+    };
+
+    xhr.onerror = function() {
+        showToast('error', 'Download failed.');
+        closeDownloadModal();
+    };
+
+    xhr.send();
+}