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/kanban/KanbanTaskCard.vue

@@ -1,6 +1,5 @@
 <script setup lang="ts">
 import { computed } from 'vue'
-import { NTooltip } from 'naive-ui'
 import { useI18n } from 'vue-i18n'
 import ProfileAvatar from '@/components/hermes/profiles/ProfileAvatar.vue'
 import type { KanbanTask } from '@/api/hermes/kanban'
@@ -40,21 +39,18 @@ const priorityText = computed(() => {
   <div class="kanban-task-card" :class="`status-${task.status}`" @click="emit('click', task.id)">
     <div class="card-title">{{ task.title }}</div>
     <div class="card-meta">
-      <NTooltip v-if="task.assignee" trigger="hover">
-        <template #trigger>
-          <span class="meta-tag assignee-tag">
-            <ProfileAvatar
-              class="assignee-profile-avatar"
-              :name="task.assignee"
-              :avatar="assigneeAvatar"
-              :size="18"
-              aria-hidden="true"
-            />
-            <span>{{ task.assignee }}</span>
-          </span>
-        </template>
-        {{ t('kanban.card.assigneeTooltip') }}
-      </NTooltip>
+      <a-tooltip v-if="task.assignee" :content="t('kanban.card.assigneeTooltip')">
+        <span class="meta-tag assignee-tag">
+          <ProfileAvatar
+            class="assignee-profile-avatar"
+            :name="task.assignee"
+            :avatar="assigneeAvatar"
+            :size="18"
+            aria-hidden="true"
+          />
+          <span>{{ task.assignee }}</span>
+        </span>
+      </a-tooltip>
       <span v-if="task.priority >= 2" class="meta-tag priority-tag" :class="priorityLabel">{{ priorityText }}</span>
       <span class="meta-time">{{ timeAgo }}</span>
     </div>