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/views/LoginView.vue

@@ -56,7 +56,7 @@ async function handleLogin() {
       <div class="login-logo">
         <img src="/logo.png" alt="Hermes" width="80" height="80" />
       </div>
-      <h1 class="login-title">Hermes Web UI</h1>
+      <h1 class="login-title">{{ t('login.title') }}</h1>
       <p class="login-desc">{{ t("login.description") }}</p>
 
       <form class="login-form" @submit.prevent="handleLogin">