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/AppSidebar.vue

@@ -0,0 +1,45 @@
+<template>
+  <aside class="hidden w-56 shrink-0 flex-col border-r border-zinc-800/80 bg-zinc-900/40 md:flex">
+    <RouterLink :to="{ name: 'dashboard' }" class="flex items-center gap-2 px-4 py-3.5">
+      <img src="/icon.svg" class="h-7 w-7" alt="" />
+      <span class="text-base font-semibold text-zinc-100">{{ t('common.appName') }}</span>
+    </RouterLink>
+    <button
+      type="button"
+      class="mx-2 mb-2 flex items-center gap-2 rounded-lg border border-zinc-800 bg-zinc-950/40 px-2.5 py-1.5 text-sm text-zinc-500 transition-colors hover:border-zinc-700 hover:text-zinc-300 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-emerald-500/50"
+      @click="palette.show()"
+    >
+      <Search :size="15" />
+      <span class="flex-1 text-left">{{ t('common.search') }}</span>
+      <kbd class="rounded border border-zinc-700 px-1 text-[10px] text-zinc-500">⌘K</kbd>
+    </button>
+    <nav class="flex flex-1 flex-col gap-1 px-2">
+      <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="row"
+      />
+    </nav>
+    <div class="border-t border-zinc-800/80 p-3">
+      <AppShellFooter />
+    </div>
+  </aside>
+</template>
+
+<script setup lang="ts">
+import { useI18n } from 'vue-i18n';
+import { Search } from '@lucide/vue';
+import { useNav } from '../../composables/useNav';
+import { useCommandPalette } from '../../composables/useCommandPalette';
+import NavItem from './NavItem.vue';
+import AppShellFooter from './AppShellFooter.vue';
+
+const { t } = useI18n();
+const { items, isActive } = useNav();
+const palette = useCommandPalette();
+</script>