P4-C: PWA installable, service worker push & campagne de fiabilité dialogues

- PWA: public/manifest.webmanifest + icon.svg + meta index.html (theme-color, apple-touch-icon)
- public/sw.js: service worker push-only (push → showNotification tag=sessionId ;
  notificationclick → focus/ouvre /sessions/<id>) — pas de précache (hors périmètre)
- lib/push.ts + stores/push.ts: enable/disable, abonnement VAPID, enregistrement SW au boot
- DashboardView: toggle « Notifications » (gardé par pushSupported) + i18n en/fr
- campagne de fiabilité (verdict S3): classification de tous les types de dialogue sur captures
  réelles (trust/permission×2/question) + refus Esc (deny-esc2) + plan (synthétique)
- acceptance-p4.mjs: VAPID/auth/Origin, subscribe idempotent/unsubscribe, answer (rejets)

Choix: SW écrit à la main plutôt que vite-plugin-pwa (qui tirait ~295 paquets Workbox +
2 vulns esbuild high pour un SW push-only). Zéro dépendance front nouvelle. 175 tests verts,
acceptance p1..p4 ALL GREEN.

packages/web/src/i18n/en.ts

@@ -97,6 +97,12 @@ export default {
     back: 'Sessions',
     notAttachable: 'This session runs outside Arboretum — fork it to interact, or resume it once it has stopped.',
   },
+  push: {
+    enable: 'Enable notifications',
+    disable: 'Notifications on',
+    denied: 'Notification permission denied — enable it in your browser settings.',
+    unsupported: 'Push needs HTTPS (e.g. Tailscale Serve); on iOS, install the app to your home screen first.',
+  },
   ws: {
     reconnecting: 'Connection lost — reconnecting…',
   },

packages/web/src/i18n/fr.ts

@@ -100,6 +100,12 @@ const fr: typeof en = {
     notAttachable:
       'Cette session tourne hors d’Arboretum — dupliquez-la pour interagir, ou reprenez-la une fois arrêtée.',
   },
+  push: {
+    enable: 'Activer les notifications',
+    disable: 'Notifications activées',
+    denied: 'Permission de notification refusée — activez-la dans les réglages du navigateur.',
+    unsupported: 'Le push nécessite HTTPS (ex. Tailscale Serve) ; sur iOS, installez d’abord l’app sur l’écran d’accueil.',
+  },
   ws: {
     reconnecting: 'Connexion perdue — reconnexion…',
   },

packages/web/src/lib/push.ts

@@ -0,0 +1,70 @@
+// Abonnement Web Push côté navigateur (P4-C). Enregistre le service worker, demande la permission,
+// s'abonne avec la clé VAPID publique du serveur, et transmet l'abonnement au daemon.
+import { api } from './api';
+import type { VapidKeyResponse } from '@arboretum/shared';
+
+const SW_URL = '/sw.js';
+
+/** Push nécessite service worker + PushManager + Notification (et un contexte sécurisé : localhost ou HTTPS). */
+export function pushSupported(): boolean {
+  return 'serviceWorker' in navigator && 'PushManager' in window && 'Notification' in window;
+}
+
+export function notificationPermission(): NotificationPermission {
+  return 'Notification' in window ? Notification.permission : 'denied';
+}
+
+export async function registerServiceWorker(): Promise<ServiceWorkerRegistration | null> {
+  if (!('serviceWorker' in navigator)) return null;
+  try {
+    return await navigator.serviceWorker.register(SW_URL);
+  } catch {
+    return null;
+  }
+}
+
+// La clé VAPID publique est transmise en base64url ; PushManager attend un BufferSource
+// adossé à un ArrayBuffer (pas SharedArrayBuffer) → on type explicitement le buffer.
+function urlBase64ToUint8Array(base64: string): Uint8Array<ArrayBuffer> {
+  const padding = '='.repeat((4 - (base64.length % 4)) % 4);
+  const b64 = (base64 + padding).replace(/-/g, '+').replace(/_/g, '/');
+  const raw = atob(b64);
+  const out = new Uint8Array(new ArrayBuffer(raw.length));
+  for (let i = 0; i < raw.length; i++) out[i] = raw.charCodeAt(i);
+  return out;
+}
+
+export async function currentSubscription(): Promise<PushSubscription | null> {
+  if (!pushSupported()) return null;
+  const reg = await navigator.serviceWorker.ready;
+  return reg.pushManager.getSubscription();
+}
+
+export type EnableResult = 'enabled' | 'denied' | 'unsupported';
+
+export async function enablePush(): Promise<EnableResult> {
+  if (!pushSupported()) return 'unsupported';
+  const permission = await Notification.requestPermission();
+  if (permission !== 'granted') return 'denied';
+  await registerServiceWorker();
+  const reg = await navigator.serviceWorker.ready;
+  const { key } = await api.get<VapidKeyResponse>('/api/v1/push/vapid-public-key');
+  const sub =
+    (await reg.pushManager.getSubscription()) ??
+    (await reg.pushManager.subscribe({ userVisibleOnly: true, applicationServerKey: urlBase64ToUint8Array(key) }));
+  const json = sub.toJSON();
+  const keys = json.keys ?? {};
+  await api.post('/api/v1/push/subscribe', { endpoint: sub.endpoint, keys: { p256dh: keys.p256dh ?? '', auth: keys.auth ?? '' } });
+  return 'enabled';
+}
+
+export async function disablePush(): Promise<void> {
+  const sub = await currentSubscription();
+  if (!sub) return;
+  try {
+    await api.post('/api/v1/push/unsubscribe', { endpoint: sub.endpoint });
+  } catch {
+    // le retrait local prime ; un échec réseau sur l'unsubscribe serveur n'est pas bloquant
+  }
+  await sub.unsubscribe();
+}

packages/web/src/main.ts

@@ -3,6 +3,10 @@ import { createPinia } from 'pinia';
 import App from './App.vue';
 import { router } from './router';
 import { i18n } from './i18n';
+import { registerServiceWorker } from './lib/push';
 import './style.css';
 
 createApp(App).use(createPinia()).use(router).use(i18n).mount('#app');
+
+// PWA (P4-C) : enregistre le service worker des notifications push si l'environnement le permet.
+void registerServiceWorker();

packages/web/src/stores/push.ts

@@ -0,0 +1,42 @@
+import { defineStore } from 'pinia';
+import { ref } from 'vue';
+import { currentSubscription, disablePush, enablePush, notificationPermission, pushSupported } from '../lib/push';
+
+export const usePushStore = defineStore('push', () => {
+  const supported = ref(pushSupported());
+  const enabled = ref(false);
+  const busy = ref(false);
+  /** null | 'denied' | 'unsupported' | message d'erreur */
+  const error = ref<string | null>(null);
+
+  async function refresh(): Promise<void> {
+    supported.value = pushSupported();
+    if (!supported.value) {
+      enabled.value = false;
+      return;
+    }
+    enabled.value = notificationPermission() === 'granted' && (await currentSubscription()) !== null;
+  }
+
+  async function toggle(): Promise<void> {
+    if (busy.value || !supported.value) return;
+    busy.value = true;
+    error.value = null;
+    try {
+      if (enabled.value) {
+        await disablePush();
+        enabled.value = false;
+      } else {
+        const r = await enablePush();
+        enabled.value = r === 'enabled';
+        if (r !== 'enabled') error.value = r;
+      }
+    } catch (e) {
+      error.value = e instanceof Error ? e.message : String(e);
+    } finally {
+      busy.value = false;
+    }
+  }
+
+  return { supported, enabled, busy, error, refresh, toggle };
+});

packages/web/src/views/DashboardView.vue

@@ -7,10 +7,21 @@
         <div class="ml-auto flex items-center gap-2">
           <RouterLink :to="{ name: 'sessions' }" class="btn">{{ t('dashboard.allSessions') }}</RouterLink>
           <button class="btn" :disabled="store.loading" @click="store.fetchAll()">{{ t('sessions.refresh') }}</button>
+          <button
+            v-if="push.supported"
+            class="btn"
+            :class="push.enabled ? 'border-emerald-700 text-emerald-300' : ''"
+            :disabled="push.busy"
+            :title="pushErrorText"
+            @click="push.toggle()"
+          >
+            {{ push.enabled ? t('push.disable') : t('push.enable') }}
+          </button>
           <LanguageSwitcher />
           <button class="btn" @click="onLogout">{{ t('common.logout') }}</button>
         </div>
       </header>
+      <p v-if="pushErrorText" class="text-xs text-amber-400">{{ pushErrorText }}</p>
 
       <form class="flex flex-col gap-2 rounded-lg border border-zinc-800 bg-zinc-900/50 p-3 sm:flex-row sm:items-end" @submit.prevent="onAddRepo">
         <label class="flex flex-1 flex-col gap-1 text-xs text-zinc-400">
@@ -33,12 +44,13 @@
 </template>
 
 <script setup lang="ts">
-import { onMounted, ref } from 'vue';
+import { computed, onMounted, ref } from 'vue';
 import { useRouter } from 'vue-router';
 import { useI18n } from 'vue-i18n';
 import { useAuthStore } from '../stores/auth';
 import { useWorktreesStore } from '../stores/worktrees';
 import { useSessionsStore } from '../stores/sessions';
+import { usePushStore } from '../stores/push';
 import LanguageSwitcher from '../components/LanguageSwitcher.vue';
 import RepoSection from '../components/RepoSection.vue';
 
@@ -47,11 +59,19 @@ const router = useRouter();
 const auth = useAuthStore();
 const store = useWorktreesStore();
 const sessions = useSessionsStore();
+const push = usePushStore();
 
 const newPath = ref('');
 const adding = ref(false);
 const addError = ref<string | null>(null);
 
+// 'denied'/'unsupported' sont des clés i18n ; tout autre message d'erreur est affiché tel quel.
+const pushErrorText = computed(() => {
+  const e = push.error;
+  if (!e) return '';
+  return e === 'denied' || e === 'unsupported' ? t(`push.${e}`) : e;
+});
+
 onMounted(() => {
   void store.fetchAll();
   store.startRealtime();
@@ -59,6 +79,7 @@ onMounted(() => {
   // suit leurs mises à jour temps réel pour que les badges d'état (busy/waiting/idle) restent live.
   void sessions.fetchSessions();
   sessions.startRealtime();
+  void push.refresh();
 });
 
 async function onAddRepo(): Promise<void> {