Phase 007: migrate every remaining view from naive-ui to Arco Design Vue

The project now has exactly one UI library. Every naive-ui component in
packages/client/src is replaced by its Arco equivalent across 24 views and
roughly 80 components, and naive-ui is dropped from package.json along with
its transitive vueuc / @css-render / vdirs / seemly dependencies.

The migration is rendering-layer only. No store logic, no API contract, and
no /chat-run payload was touched.

Three classes of leftover were invisible to `grep naive-ui` and are now
covered by tests/client/no-naive-ui.test.ts, which asserts all three:
  - dead .n-* class names in style blocks
  - dead --n-* custom properties
  - naive-ui in package.json

Notable behavioural traps handled along the way, recorded in
docs/arco-migration-rules.md:
  - a-input-password defaults to masked; passing default-visibility="false"
    would have exposed API keys in clear text
  - a-upload fires a real XHR unless auto-upload is false
  - nested Trigger components fight over the first element child, so the
    group-chat settings dropdown was flattened
  - Arco renders tooltip default-slot text inline, which was silently
    collapsing the chat and group-chat toolbars

packages/client/src/components/hermes/settings/DisplaySettings.vue

@@ -1,6 +1,5 @@
 <script setup lang="ts">
 import { computed } from 'vue'
-import { NButton, NSwitch, NSelect, NInputNumber } from 'naive-ui'
 import { useMessage } from '@/composables/useMessage'
 import { useI18n } from 'vue-i18n'
 import { useSettingsStore } from '@/stores/hermes/settings'
@@ -92,51 +91,51 @@ async function testCompletionNotification() {
 <template>
   <section class="settings-section">
     <SettingRow :label="t('settings.display.theme')" :hint="t('settings.display.themeHint')">
-      <NSelect :value="brightness" :options="themeOptions" size="small" :consistent-menu-width="false" class="input-sm" @update:value="handleThemeChange" />
+      <a-select :model-value="brightness" :options="themeOptions" size="small" class="input-sm" @update:model-value="v => handleThemeChange(String(v))" />
     </SettingRow>
     <SettingRow :label="t('settings.display.streaming')" :hint="t('settings.display.streamingHint')">
-      <NSwitch :value="settingsStore.display.streaming" @update:value="v => save({ streaming: v })" />
+      <a-switch :model-value="settingsStore.display.streaming" @update:model-value="v => save({ streaming: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.compact')" :hint="t('settings.display.compactHint')">
-      <NSwitch :value="settingsStore.display.compact" @update:value="v => save({ compact: v })" />
+      <a-switch :model-value="settingsStore.display.compact" @update:model-value="v => save({ compact: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.showReasoning')" :hint="t('settings.display.showReasoningHint')">
-      <NSwitch :value="settingsStore.display.show_reasoning" @update:value="v => save({ show_reasoning: v })" />
+      <a-switch :model-value="settingsStore.display.show_reasoning" @update:model-value="v => save({ show_reasoning: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.showCost')" :hint="t('settings.display.showCostHint')">
-      <NSwitch :value="settingsStore.display.show_cost" @update:value="v => save({ show_cost: v })" />
+      <a-switch :model-value="settingsStore.display.show_cost" @update:model-value="v => save({ show_cost: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.inlineDiffs')" :hint="t('settings.display.inlineDiffsHint')">
-      <NSwitch :value="settingsStore.display.inline_diffs" @update:value="v => save({ inline_diffs: v })" />
+      <a-switch :model-value="settingsStore.display.inline_diffs" @update:model-value="v => save({ inline_diffs: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.bellOnComplete')" :hint="t('settings.display.bellOnCompleteHint')">
-      <NSwitch :value="settingsStore.display.bell_on_complete" @update:value="v => save({ bell_on_complete: v })" />
+      <a-switch :model-value="settingsStore.display.bell_on_complete" @update:model-value="v => save({ bell_on_complete: v })" />
     </SettingRow>
     <SettingRow :label="t('settings.display.notifyOnComplete')" :hint="`${t('settings.display.notifyOnCompleteHint')} ${t('settings.display.notifyOnCompleteMacHint')}`">
       <div class="notify-controls">
-        <NSwitch :value="settingsStore.display.notify_on_complete" @update:value="handleNotifyOnCompleteChange" />
-        <NButton size="tiny" secondary @click="testCompletionNotification">
+        <a-switch :model-value="settingsStore.display.notify_on_complete" @update:model-value="v => handleNotifyOnCompleteChange(v as boolean)" />
+        <a-button size="mini" type="secondary" @click="testCompletionNotification">
           {{ t('settings.display.notifyOnCompleteTestButton') }}
-        </NButton>
+        </a-button>
       </div>
     </SettingRow>
     <SettingRow :label="t('settings.display.chatInputHeight')" :hint="t('settings.display.chatInputHeightHint')">
       <div class="chat-input-height-controls">
-        <NInputNumber
-          :value="chatInputHeight"
+        <a-input-number
+          :model-value="chatInputHeight ?? undefined"
           :min="MIN_CHAT_INPUT_HEIGHT"
           :max="MAX_CHAT_INPUT_HEIGHT"
           :step="8"
-          :show-button="false"
+          hide-button
           size="small"
           class="input-sm"
-          @update:value="handleChatInputHeightChange"
+          @update:model-value="v => handleChatInputHeightChange(v ?? null)"
         >
           <template #suffix>px</template>
-        </NInputNumber>
-        <NButton size="tiny" secondary @click="resetChatInputHeight">
+        </a-input-number>
+        <a-button size="mini" type="secondary" @click="resetChatInputHeight">
           {{ t('common.reset') }}
-        </NButton>
+        </a-button>
       </div>
     </SettingRow>
   </section>