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/layout/MobileTabBar.vue

@@ -0,0 +1,40 @@
+<template>
+  <nav
+    class="fixed inset-x-0 bottom-0 z-40 flex border-t border-zinc-800 bg-zinc-950/95 backdrop-blur md:hidden"
+    style="padding-bottom: env(safe-area-inset-bottom)"
+  >
+    <NavItem
+      v-for="item in items"
+      :key="item.key"
+      :to="item.to"
+      :icon="item.icon"
+      :label="item.label"
+      :badge="item.badge"
+      :active="isActive(item.match)"
+      orientation="col"
+      class="flex-1"
+    />
+    <button
+      type="button"
+      class="flex flex-1 flex-col items-center gap-0.5 py-2 text-zinc-500 transition-colors hover:text-zinc-300 focus-visible:outline-none"
+      @click="showMore = true"
+    >
+      <Settings :size="20" :stroke-width="1.75" />
+      <span class="text-[10px]">{{ t('nav.settings') }}</span>
+    </button>
+    <MoreSheet v-if="showMore" @close="showMore = false" />
+  </nav>
+</template>
+
+<script setup lang="ts">
+import { ref } from 'vue';
+import { useI18n } from 'vue-i18n';
+import { Settings } from '@lucide/vue';
+import { useNav } from '../../composables/useNav';
+import NavItem from './NavItem.vue';
+import MoreSheet from './MoreSheet.vue';
+
+const { t } = useI18n();
+const { items, isActive } = useNav();
+const showMore = ref(false);
+</script>