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/jobs/JobCard.vue

@@ -95,7 +95,7 @@ async function handleDelete() {
         <span class="info-value">
           {{ formatTime(job.last_run_at) }}
           <span v-if="job.last_status" class="run-status" :class="{ ok: job.last_status === 'ok', err: job.last_status !== 'ok' }">
-            {{ job.last_status === 'ok' ? 'OK' : job.last_status }}
+            {{ job.last_status === 'ok' ? t('common.ok') : job.last_status }}
           </span>
         </span>
       </div>