more work on webhook, implement getMetadata endpoint for appview and link holds to a preferred appview

pkg/appview/src/css/main.css

@@ -420,6 +420,16 @@
     .vuln-box-low { background-color: oklch(80% 0.1 85); color: oklch(25% 0.05 85); }
 }
 
+/* ========================================
+   TOAST CONTAINER
+   ======================================== */
+#toast-container {
+    pointer-events: none;
+}
+#toast-container > * {
+    pointer-events: auto;
+}
+
 /* ========================================
    SUPPORTER BADGE TEXT COLOR OVERRIDES
    Unlayered — wins over DaisyUI's layered

pkg/appview/src/js/app.js

@@ -711,6 +711,46 @@ document.addEventListener('DOMContentLoaded', () => {
     }
 });
 
+// Toast notifications (auto-dismiss after 3s)
+function showToast(message, type) {
+    let container = document.getElementById('toast-container');
+    if (!container) {
+        container = document.createElement('div');
+        container.id = 'toast-container';
+        container.className = 'toast toast-end toast-bottom z-50';
+        document.body.appendChild(container);
+    }
+
+    const alertClass = type === 'error' ? 'alert-error' : 'alert-success';
+    const toast = document.createElement('div');
+    toast.className = `alert ${alertClass} shadow-lg transition-opacity duration-300`;
+    toast.innerHTML = `<span>${message}</span>`;
+    container.appendChild(toast);
+
+    setTimeout(() => {
+        toast.style.opacity = '0';
+        setTimeout(() => toast.remove(), 300);
+    }, 3000);
+}
+
+// Test webhook via fetch + toast
+async function testWebhook(rkey) {
+    try {
+        const resp = await fetch(`/api/webhooks/${rkey}/test`, {
+            method: 'POST',
+            credentials: 'include',
+        });
+        const text = await resp.text();
+        if (text.includes('class="success"') || (resp.ok && !text.includes('class="error"'))) {
+            showToast('Test webhook delivered successfully!', 'success');
+        } else {
+            showToast('Test delivery failed \u2014 check the webhook URL', 'error');
+        }
+    } catch {
+        showToast('Failed to reach server', 'error');
+    }
+}
+
 // Export functions that are called from templates via onclick handlers
 window.setTheme = setTheme;
 window.toggleSearch = toggleSearch;
@@ -720,3 +760,5 @@ window.toggleOfflineManifests = toggleOfflineManifests;
 window.deleteManifest = deleteManifest;
 window.closeManifestDeleteModal = closeManifestDeleteModal;
 window.openVulnDetails = openVulnDetails;
+window.showToast = showToast;
+window.testWebhook = testWebhook;