feat(redesign): design-system tokens, 23 Vue components, game-aware shell + Fleet/Solo dashboard

Tokens ported 1:1 from the Claude Design bundle (colors/game-themes/type/spacing/elevation/motion/fonts) with the data-theme/data-game theming contract via useThemeGame (+ cc-skin-swap repaint guard). 23 design-system components reimplemented as Vue SFCs (core/forms/data/navigation/feedback/brand). DashboardLayout rebuilt as the game-aware shell (GameSwitcher, grouped nav with permission gating preserved, agent-health footer, topbar). DashboardView: Fleet + Solo with per-game GAME_FIELDS rows and the themed ECharts PlayersChart; Solo wired to the real server store, Fleet on representative data pending the multi-instance backend. All four game skins (Rust/Dune/Conan/Soulmask). vue-tsc + vite build green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/ds/feedback/EmptyState.vue

@@ -0,0 +1,39 @@
+<script setup lang="ts">
+/**
+ * EmptyState — zero-data placeholder with icon, title, description, and an
+ * optional action slot (pass a Button or link).
+ *
+ * Icon registry note: default icon 'inbox' is not in the registry — it will
+ * silently not render per Icon.vue's null guard. Callers should pass a
+ * registered icon name (e.g. icon="server", icon="folder-open").
+ */
+import Icon from '@/components/ds/core/Icon.vue'
+
+withDefaults(
+  defineProps<{
+    icon?: string
+    title?: string
+    description?: string
+  }>(),
+  { icon: 'inbox' },
+)
+</script>
+
+<template>
+  <div class="cc-empty">
+    <div class="cc-empty__icon">
+      <Icon :name="icon" :size="22" :stroke-width="1.75" />
+    </div>
+    <div v-if="title" class="cc-empty__title">{{ title }}</div>
+    <div v-if="description" class="cc-empty__desc">{{ description }}</div>
+    <div v-if="$slots.action" class="cc-empty__action"><slot name="action" /></div>
+  </div>
+</template>
+
+<style>
+.cc-empty { display:flex; flex-direction:column; align-items:center; text-align:center; gap:5px; padding:36px 24px; }
+.cc-empty__icon { width:46px; height:46px; border-radius:var(--radius-lg); display:flex; align-items:center; justify-content:center; margin-bottom:8px; color:var(--text-tertiary); background:var(--surface-raised-2); box-shadow:var(--ring-default); }
+.cc-empty__title { font-size:var(--text-base); font-weight:600; color:var(--text-primary); }
+.cc-empty__desc { font-size:var(--text-sm); color:var(--text-tertiary); max-width:340px; line-height:1.5; }
+.cc-empty__action { margin-top:12px; }
+</style>