feat: comprehensive documentation and demo updates

- Update READMEs and docs across multiple languages
- Enhance interactive demos for Agent, LLM, VLM, Audio, Image Gen, Terminal, and Web Basics
- Add new appendix sections for Database and IDE intros
- Update VitePress config, theme, and utility scripts
- Clean up unused assets and components

docs/.vitepress/theme/components/appendix/git-intro/GitStashDemo.vue

@@ -0,0 +1,60 @@
+<template>
+  <div class="stash-demo">
+    <div class="panel">
+      <div class="areas">
+        <div class="area">
+          <div class="header">💻 工作区 ({{ work.length }})</div>
+          <div v-for="f in work" :key="f" class="file">📄 {{ f }}</div>
+          <div v-if="work.length === 0" class="empty">空</div>
+        </div>
+
+        <div class="area">
+          <div class="header">📚 Stash 栈 ({{ stash.length }})</div>
+          <div v-for="(s,i) in stash" :key="i" class="stash-item">
+            <span class="num">{{ i+1 }}</span>
+            <span class="msg">{{ s }}</span>
+          </div>
+          <div v-if="stash.length === 0" class="empty">空</div>
+        </div>
+      </div>
+
+      <div class="controls">
+        <button @click="doWork" :disabled="work.length > 0" class="btn">修改</button>
+        <button @click="save" :disabled="work.length === 0 || stash.length >= 3" class="btn">保存</button>
+        <button @click="pop" :disabled="stash.length === 0" class="btn">恢复</button>
+        <button @click="reset" class="btn secondary">重置</button>
+      </div>
+    </div>
+
+    <div class="info-box">
+      <p><strong>💡 Stash 用途:</strong> 临时保存工作现场，切换任务</p>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+const work = ref([])
+const stash = ref([])
+const doWork = () => { work.value = ['file.js', 'style.css'] }
+const save = () => { stash.value.push('WIP'); work.value = [] }
+const pop = () => { if(stash.value.length) { stash.value.pop(); work.value = ['file.js'] } }
+const reset = () => { work.value = []; stash.value = [] }
+</script>
+
+<style scoped>
+.stash-demo { border: 1px solid var(--vp-c-divider); border-radius: 8px; background-color: var(--vp-c-bg-soft); padding: 1.5rem; margin: 1rem 0; }
+.areas { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 1rem; }
+.area { border: 1px solid var(--vp-c-divider); border-radius: 8px; padding: 1rem; background: var(--vp-c-bg); }
+.header { font-weight: 600; margin-bottom: 0.5rem; padding-bottom: 0.5rem; border-bottom: 1px solid var(--vp-c-divider); }
+.file, .stash-item { padding: 0.5rem; background: var(--vp-c-bg-soft); margin-bottom: 0.25rem; border-radius: 4px; font-size: 0.875rem; display: flex; gap: 0.5rem; align-items: center; }
+.stash-item .num { width: 20px; height: 20px; background: var(--vp-c-brand); color: white; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 0.75rem; }
+.empty { color: var(--vp-c-text-3); text-align: center; font-style: italic; padding: 1rem; }
+.controls { display: flex; gap: 0.5rem; flex-wrap: wrap; }
+.btn { padding: 0.5rem 1rem; border: 1px solid var(--vp-c-brand); background: var(--vp-c-bg); color: var(--vp-c-brand); border-radius: 6px; cursor: pointer; }
+.btn:hover:not(:disabled) { background: var(--vp-c-brand); color: var(--vp-c-bg); }
+.btn:disabled { opacity: 0.5; cursor: not-allowed; }
+.btn.secondary { border-color: var(--vp-c-divider); }
+.info-box { padding: 1rem; background: var(--vp-c-bg); border-left: 4px solid var(--vp-c-brand); border-radius: 4px; margin-top: 1rem; }
+.info-box p { margin: 0; color: var(--vp-c-text-1); }
+</style>