feat: add webchat pwa push subscription support

src/gateway/ui/pages/settings.js

@@ -4,6 +4,12 @@
  * Read-only config view (redacted), editable hook patterns,
  * tool list, and channel overview.
  */
+import {
+  isPushSupported,
+  getPushStatus,
+  enablePushNotifications,
+  disablePushNotifications,
+} from '../lib/pwa.js';
 
 function escapeHtml(text) {
   const div = document.createElement('div');
@@ -14,6 +20,75 @@ function escapeHtml(text) {
 let _client = null;
 let _el = null;
 
+function describePushStatus(status) {
+  if (!status.supported) {
+    return status.message || 'Push notifications are not supported in this browser.';
+  }
+  if (!status.enabled) {
+    return 'Gateway push is disabled (`server.webchat_push.enabled: false`).';
+  }
+  if (!status.configured) {
+    return 'Gateway push key is missing (`server.webchat_push.vapid_public_key`).';
+  }
+  if (status.permission === 'denied') {
+    return 'Browser notifications are blocked. Allow notifications in browser settings.';
+  }
+  if (status.subscribed) {
+    return 'Push notifications are enabled for this browser.';
+  }
+  return 'Push is configured. Click Enable to subscribe this browser.';
+}
+
+async function renderPushStatus() {
+  const statusEl = _el.querySelector('#push-status');
+  const enableBtn = _el.querySelector('#push-enable');
+  const disableBtn = _el.querySelector('#push-disable');
+  if (!statusEl || !enableBtn || !disableBtn) {
+    return;
+  }
+
+  try {
+    const status = await getPushStatus();
+    statusEl.textContent = describePushStatus(status);
+    statusEl.className = status.subscribed ? 'text-sm text-success' : 'text-sm text-muted';
+    enableBtn.disabled = !status.supported || !status.enabled || !status.configured || status.subscribed;
+    disableBtn.disabled = !status.supported || !status.subscribed;
+  } catch (err) {
+    statusEl.textContent = `Push status error: ${err.message}`;
+    statusEl.className = 'text-sm text-error';
+    enableBtn.disabled = true;
+    disableBtn.disabled = true;
+  }
+}
+
+async function onEnablePush() {
+  const statusEl = _el.querySelector('#push-status');
+  if (!statusEl) {return;}
+  statusEl.textContent = 'Enabling push notifications...';
+  statusEl.className = 'text-sm text-muted';
+  try {
+    await enablePushNotifications();
+    await renderPushStatus();
+  } catch (err) {
+    statusEl.textContent = `Enable failed: ${err.message}`;
+    statusEl.className = 'text-sm text-error';
+  }
+}
+
+async function onDisablePush() {
+  const statusEl = _el.querySelector('#push-status');
+  if (!statusEl) {return;}
+  statusEl.textContent = 'Disabling push notifications...';
+  statusEl.className = 'text-sm text-muted';
+  try {
+    await disablePushNotifications();
+    await renderPushStatus();
+  } catch (err) {
+    statusEl.textContent = `Disable failed: ${err.message}`;
+    statusEl.className = 'text-sm text-error';
+  }
+}
+
 async function loadSettings() {
   if (!_client || !_el) {return;}
 
@@ -52,6 +127,16 @@ async function loadSettings() {
   _el.innerHTML = `
     <h1 class="page-title">Settings</h1>
 
+    <h2 class="section-title">WebChat Push Notifications</h2>
+    <div class="settings-section">
+      ${isPushSupported() ? '' : '<div class="text-sm text-muted">This browser does not support PushManager APIs.</div>'}
+      <div style="display: flex; gap: 8px; margin-bottom: 8px;">
+        <button id="push-enable" class="btn btn-primary" type="button">Enable Push</button>
+        <button id="push-disable" class="btn btn-secondary" type="button">Disable Push</button>
+      </div>
+      <div id="push-status" class="text-sm text-muted"></div>
+    </div>
+
     <h2 class="section-title">Hook Patterns</h2>
     <div class="settings-section">
       <div class="hook-editor">
@@ -133,6 +218,9 @@ async function loadSettings() {
 
   // Bind save hooks
   _el.querySelector('#hooks-save').addEventListener('click', saveHooks);
+  _el.querySelector('#push-enable').addEventListener('click', onEnablePush);
+  _el.querySelector('#push-disable').addEventListener('click', onDisablePush);
+  await renderPushStatus();
 }
 
 async function saveHooks() {