feat(appendix): 添加多个交互式演示组件，完善 AI/Infra 等章节内容

- 新增 Vibe Coding 全栈相关演示组件 (DeveloperSkillShift, FrontendTriad, BackendCore 等)
- 新增 RAG 相关组件 (RAGPipeline, ChunkingStrategy, Retrieval 等)
- 新增 Embedding & Vector 相关组件 (EmbeddingConcept, VectorSimilarity 等)
- 新增 AI Native App 设计组件 (AINativeArch, PromptDesign 等)
- 新增 Infrastructure as Code 组件 (IaCConcept, TerraformWorkflow 等)
- 新增 DNS & HTTPS 演示组件 (DnsResolution, HttpsHandshake 等)
- 新增 Model Finetuning 组件 (FinetuningPipeline 等)
- 更新多个章节的 markdown 内容，集成交互式演示

docs/.vitepress/theme/components/appendix/computer-fundamentals/DesktopDemo.vue

@@ -0,0 +1,172 @@
+<template>
+  <div class="desktop-demo">
+    <div class="demo-label">桌面是如何出现的 ── 点击加载</div>
+
+    <div class="desktop-view" @click="loading = !loading">
+      <div class="screen" :class="{ loaded: loading }">
+        <div class="boot-screen" v-if="!loading">
+          <div class="boot-logo">⚙️</div>
+          <div class="boot-text">正在启动...</div>
+        </div>
+        <div class="desktop" v-else>
+          <div class="desktop-icons">
+            <div class="desktop-icon">📁</div>
+            <div class="desktop-icon">🗑️</div>
+            <div class="desktop-icon">⚙️</div>
+            <div class="desktop-icon">🌐</div>
+          </div>
+          <div class="taskbar">
+            <div class="taskbar-icon">🏠</div>
+            <div class="taskbar-icon">📊</div>
+            <div class="taskbar-time">{{ time }}</div>
+          </div>
+        </div>
+      </div>
+    </div>
+
+    <div class="tap-hint">👆 点击切换开机状态</div>
+  </div>
+</template>
+
+<script setup>
+import { ref, onMounted, onUnmounted } from 'vue'
+
+const loading = ref(false)
+const time = ref('')
+
+let timer = null
+
+const updateTime = () => {
+  const now = new Date()
+  time.value = now.toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' })
+}
+
+onMounted(() => {
+  updateTime()
+  timer = setInterval(updateTime, 1000)
+})
+
+onUnmounted(() => {
+  if (timer) clearInterval(timer)
+})
+</script>
+
+<style scoped>
+.desktop-demo {
+  border: 1px solid var(--vp-c-divider);
+  border-radius: 8px;
+  background: var(--vp-c-bg-soft);
+  padding: 1rem 1.2rem;
+  margin: 1rem 0;
+  cursor: pointer;
+  user-select: none;
+}
+
+.demo-label {
+  font-size: 0.78rem;
+  font-weight: bold;
+  color: var(--vp-c-text-2);
+  margin-bottom: 0.75rem;
+  letter-spacing: 0.2px;
+}
+
+.desktop-view {
+  display: flex;
+  justify-content: center;
+}
+
+.screen {
+  width: 14rem;
+  height: 9rem;
+  background: #1a1a1a;
+  border-radius: 6px;
+  overflow: hidden;
+  transition: all 0.5s;
+}
+
+.screen.loaded {
+  background: linear-gradient(180deg, #2d5af5 0%, #1e3a8a 100%);
+}
+
+.boot-screen {
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  color: #666;
+}
+
+.boot-logo {
+  font-size: 2rem;
+  margin-bottom: 0.5rem;
+  animation: spin 2s linear infinite;
+}
+
+@keyframes spin {
+  from { transform: rotate(0deg); }
+  to { transform: rotate(360deg); }
+}
+
+.boot-text {
+  font-size: 0.75rem;
+}
+
+.desktop {
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+  justify-content: space-between;
+  padding: 0.5rem;
+}
+
+.desktop-icons {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+}
+
+.desktop-icon {
+  width: 2.2rem;
+  height: 2.2rem;
+  background: rgba(255,255,255,0.15);
+  border-radius: 4px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 1.2rem;
+}
+
+.taskbar {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  background: rgba(0,0,0,0.3);
+  padding: 0.3rem 0.5rem;
+  border-radius: 4px;
+}
+
+.taskbar-icon {
+  width: 1.5rem;
+  height: 1.5rem;
+  background: rgba(255,255,255,0.2);
+  border-radius: 3px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 0.8rem;
+}
+
+.taskbar-time {
+  margin-left: auto;
+  font-size: 0.7rem;
+  color: white;
+}
+
+.tap-hint {
+  text-align: center;
+  font-size: 0.72rem;
+  color: var(--vp-c-text-3);
+  margin-top: 0.75rem;
+}
+</style>