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/models/ProviderFormModal.vue

@@ -36,7 +36,7 @@ function autoGenerateName(url: string): string {
   const clean = url.replace(/^https?:\/\//, '').replace(/\/v1\/?$/, '')
   const host = clean.split('/')[0]
   if (host.includes('localhost') || host.includes('127.0.0.1')) {
-    return `Local (${host})`
+    return t('models.local', { host })
   }
   return host.charAt(0).toUpperCase() + host.slice(1)
 }