feat: refonte UX du dashboard (coquille, tri/filtre/pagination, ⌘K, toasts)

Refonte front (packages/web) : coquille applicative partagée (sidebar desktop +
barre d'onglets mobile + PageHeader, langue/push/logout centralisés) pilotée par
route.meta.layout ; design system (BaseButton/BaseBadge/SegmentedControl/EmptyState/
SkeletonRow, anneau de focus, icônes @lucide/vue) ; tri/filtre/recherche/pagination
côté client via useListControls (+ synchro URL) sur sessions/worktrees/groupes ;
section « À traiter », palette de commandes ⌘K, toasts. Aucune modif serveur/protocole/DB.

packages/web/src/App.vue

@@ -1,20 +1,25 @@
 <template>
-  <div class="flex h-full flex-col">
-    <div
-      v-if="wsReconnecting"
-      class="border-b border-amber-900/50 bg-amber-950/80 px-4 py-1.5 text-center text-xs text-amber-300"
-    >
-      {{ t('ws.reconnecting') }}
-    </div>
-    <RouterView class="min-h-0 flex-1" />
+  <div class="flex h-dvh flex-col">
+    <WsBanner v-if="wsReconnecting" />
+    <AppShell v-if="layout !== 'bare'" :fullbleed="layout === 'fullbleed'">
+      <RouterView />
+    </AppShell>
+    <RouterView v-else class="min-h-0 flex-1" />
+    <ToastContainer />
+    <CommandPalette />
   </div>
 </template>
 
 <script setup lang="ts">
 import { computed } from 'vue';
-import { useI18n } from 'vue-i18n';
+import { useRoute } from 'vue-router';
 import { wsClient } from './lib/ws-client';
+import WsBanner from './components/layout/WsBanner.vue';
+import AppShell from './components/layout/AppShell.vue';
+import ToastContainer from './components/ToastContainer.vue';
+import CommandPalette from './components/CommandPalette.vue';
 
-const { t } = useI18n();
+const route = useRoute();
+const layout = computed(() => route.meta.layout ?? 'shell');
 const wsReconnecting = computed(() => wsClient.status.value === 'reconnecting');
 </script>