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/SkillsView.vue

@@ -69,7 +69,7 @@ function handleSelect(category: string, skill: string) {
     </header>
 
     <div class="skills-content">
-      <div v-if="loading && categories.length === 0" class="skills-loading">Loading...</div>
+      <div v-if="loading && categories.length === 0" class="skills-loading">{{ t('common.loading') }}</div>
       <div v-else class="skills-layout">
           <div class="mobile-backdrop" :class="{ active: showSidebar }" @click="showSidebar = false" />
           <div v-if="showSidebar" class="skills-sidebar">
@@ -92,7 +92,7 @@ function handleSelect(category: string, skill: string) {
                 <polyline points="2 17 12 22 22 17" />
                 <polyline points="2 12 12 17 22 12" />
               </svg>
-              <span>Select a skill from the list</span>
+              <span>{{ t('skills.noMatch') }}</span>
             </div>
           </div>
         </div>