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/composables/useNav.ts

@@ -0,0 +1,36 @@
+import { computed, type Component } from 'vue';
+import { useRoute, type RouteLocationRaw } from 'vue-router';
+import { useI18n } from 'vue-i18n';
+import { GitBranch, TerminalSquare, Boxes } from '@lucide/vue';
+import { useSessionsStore } from '../stores/sessions';
+
+export interface NavEntry {
+  key: string;
+  to: RouteLocationRaw;
+  icon: Component;
+  label: string;
+  match: string[]; // noms de routes considérés actifs pour cet item
+  badge: number;
+}
+
+/** Définition unique de la navigation, partagée par la sidebar et la barre d'onglets. */
+export function useNav() {
+  const { t } = useI18n();
+  const route = useRoute();
+  const sessions = useSessionsStore();
+
+  // sessions vivantes bloquées sur un dialogue (le cœur de la supervision mobile).
+  const waitingCount = computed(
+    () => sessions.sessions.filter((s) => s.live && s.activity === 'waiting').length,
+  );
+
+  const items = computed<NavEntry[]>(() => [
+    { key: 'worktrees', to: { name: 'dashboard' }, icon: GitBranch, label: t('nav.worktrees'), match: ['dashboard'], badge: 0 },
+    { key: 'sessions', to: { name: 'sessions' }, icon: TerminalSquare, label: t('nav.sessions'), match: ['sessions', 'session'], badge: waitingCount.value },
+    { key: 'groups', to: { name: 'groups' }, icon: Boxes, label: t('nav.groups'), match: ['groups', 'group'], badge: 0 },
+  ]);
+
+  const isActive = (match: string[]): boolean => match.includes(String(route.name));
+
+  return { items, isActive, waitingCount };
+}