fix(chat): repair Arco migration fallout in the chat page

The Phase 006 walkthrough surfaced four issues the automated checks could
not see. Dead naive-ui class names left behind by the migration stopped
matching, tooltips that carried their label as trailing default-slot text
leaked that text into the flex row, the workspace panel squeezed the chat
column until the input toolbar wrapped, and the Escape fallback still
looked for naive-ui's modal mask.

Tooltips now pass their label through the content prop, the tool panel
reserves a minimum width for the chat column, and Escape finds the visible
Arco modal and clicks its close button.

packages/client/src/components/hermes/chat/TerminalPanel.vue

@@ -473,7 +473,7 @@ onUnmounted(() => {
     >
       <div class="sidebar-header">
         <span class="sidebar-title">{{ t("terminal.sessions") }}</span>
-        <a-tooltip trigger="hover">
+        <a-tooltip trigger="hover" :content="t('terminal.newTab')">
           <a-button type="secondary" size="mini" @click="createSession" shape="circle">
             <template #icon>
               <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
@@ -482,7 +482,6 @@ onUnmounted(() => {
               </svg>
             </template>
           </a-button>
-          {{ t("terminal.newTab") }}
         </a-tooltip>
       </div>
       <div class="session-list">