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/ui/SegmentedControl.vue

@@ -0,0 +1,30 @@
+<template>
+  <div class="inline-flex rounded-lg border border-zinc-800 bg-zinc-950/40 p-0.5">
+    <button
+      v-for="opt in options"
+      :key="opt.value"
+      type="button"
+      class="inline-flex items-center gap-1.5 rounded-md px-2.5 py-1 text-xs font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-emerald-500/70"
+      :class="opt.value === modelValue ? 'bg-zinc-800 text-zinc-100' : 'text-zinc-400 hover:text-zinc-200'"
+      :aria-pressed="opt.value === modelValue"
+      @click="emit('update:modelValue', opt.value)"
+    >
+      <component :is="opt.icon" v-if="opt.icon" :size="15" />
+      <span v-if="opt.label">{{ opt.label }}</span>
+    </button>
+  </div>
+</template>
+
+<script setup lang="ts">
+// Bascule segmentée (ex. liste / grille) : remplace le toggle bricolé inline.
+import type { Component } from 'vue';
+
+export interface SegmentOption {
+  value: string;
+  label?: string;
+  icon?: Component;
+}
+
+defineProps<{ modelValue: string; options: SegmentOption[] }>();
+const emit = defineEmits<{ 'update:modelValue': [string] }>();
+</script>