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/components/ToastContainer.vue

@@ -0,0 +1,60 @@
+<template>
+  <div class="pointer-events-none fixed inset-x-0 bottom-0 z-50 flex flex-col items-end gap-2 p-4 sm:bottom-4 sm:right-4 sm:left-auto sm:p-0">
+    <TransitionGroup name="toast">
+      <div
+        v-for="toast in store.toasts"
+        :key="toast.id"
+        class="pointer-events-auto flex w-full max-w-sm items-start gap-2 rounded-lg border px-3 py-2 shadow-pop"
+        :class="toneClass(toast.kind)"
+        :role="toast.kind === 'error' ? 'alert' : 'status'"
+        :aria-live="toast.kind === 'error' ? 'assertive' : 'polite'"
+      >
+        <component :is="icon(toast.kind)" :size="16" class="mt-0.5 shrink-0" />
+        <span class="min-w-0 flex-1 break-words text-sm">{{ toast.message }}</span>
+        <button
+          class="shrink-0 rounded p-0.5 opacity-70 transition-opacity hover:opacity-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-zinc-400/50"
+          :aria-label="t('toast.dismiss')"
+          @click="store.dismiss(toast.id)"
+        >
+          <X :size="14" />
+        </button>
+      </div>
+    </TransitionGroup>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { useI18n } from 'vue-i18n';
+import { CheckCircle2, AlertTriangle, Info, X } from '@lucide/vue';
+import { useToastsStore, type ToastKind } from '../stores/toasts';
+
+const { t } = useI18n();
+const store = useToastsStore();
+
+function toneClass(kind: ToastKind): string {
+  if (kind === 'success') return 'border-emerald-800 bg-emerald-950 text-emerald-200';
+  if (kind === 'error') return 'border-red-800 bg-red-950 text-red-200';
+  return 'border-zinc-700 bg-zinc-900 text-zinc-200';
+}
+function icon(kind: ToastKind) {
+  return kind === 'success' ? CheckCircle2 : kind === 'error' ? AlertTriangle : Info;
+}
+</script>
+
+<style scoped>
+.toast-enter-active,
+.toast-leave-active {
+  transition: opacity 0.18s ease, transform 0.18s ease;
+}
+.toast-enter-from,
+.toast-leave-to {
+  opacity: 0;
+  transform: translateY(8px);
+}
+@media (prefers-reduced-motion: reduce) {
+  .toast-enter-active,
+  .toast-leave-active {
+    transition: none;
+  }
+}
+</style>