feat: add web terminal, improve README, fix node-pty and i18n issues

- Add web terminal view with xterm.js and node-pty WebSocket backend
- Rewrite README with badges, feature table, mobile demo video
- Add package keywords and improved description for npm/GitHub SEO
- Fix node-pty spawn-helper missing execute permission after npm install -g
- Auto-fix node-pty permissions on CLI startup
- Fix duplicate 'error' key in en.ts and zh.ts i18n files
- Remove nested NSpin in PlatformSettings (causes invisible loading spinner)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/layout/ModelSelector.vue

@@ -2,6 +2,9 @@
 import { computed } from 'vue'
 import { NSelect } from 'naive-ui'
 import { useAppStore } from '@/stores/app'
+import { useI18n } from 'vue-i18n'
+
+const { t } = useI18n()
 
 const appStore = useAppStore()
 
@@ -26,7 +29,7 @@ function handleChange(value: string | number | Array<string | number>) {
 
 <template>
   <div class="model-selector">
-    <div class="model-label">Model</div>
+    <div class="model-label">{{ t('models.title') }}</div>
     <NSelect
       :value="appStore.selectedModel"
       :options="options"