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/RenderingDemo.vue

@@ -0,0 +1,131 @@
+<template>
+  <div class="rendering-demo">
+    <div class="demo-label">浏览器渲染过程 ── 点击逐步演示</div>
+
+    <div class="pipeline">
+      <div
+        v-for="(stage, index) in stages"
+        :key="stage.name"
+        class="pipeline-stage"
+        :class="{ active: currentStage >= index }"
+        @click="currentStage = index"
+      >
+        <div class="stage-header">
+          <span class="stage-num">{{ index + 1 }}</span>
+          <span class="stage-name">{{ stage.name }}</span>
+        </div>
+        <div class="stage-desc">{{ stage.desc }}</div>
+        <div v-if="currentStage >= index" class="stage-detail">
+          {{ stage.detail }}
+        </div>
+      </div>
+    </div>
+
+    <div class="tap-hint">👆 点击查看各阶段详情</div>
+  </div>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+const currentStage = ref(0)
+const stages = [
+  { name: 'HTML 解析', desc: '把 HTML 变成 DOM 树', detail: '<div> → Document Object Model 树结构' },
+  { name: 'CSS 解析', desc: '把 CSS 变成样式规则', detail: '选择器 + 属性 → 样式规则表' },
+  { name: '渲染树', desc: 'DOM + CSS = 渲染树', detail: '哪些节点显示、什么样式' },
+  { name: '布局计算', desc: '计算每个元素的位置', detail: '宽高、坐标、层级' },
+  { name: '绘制', desc: '把内容画到像素缓冲区', detail: '文字、颜色、图片、边框' },
+  { name: '合成', desc: '多层合成一张图', detail: 'GPU 合成，显示到屏幕' }
+]
+</script>
+
+<style scoped>
+.rendering-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;
+}
+
+.pipeline {
+  display: flex;
+  flex-direction: column;
+  gap: 0.4rem;
+}
+
+.pipeline-stage {
+  background: var(--vp-c-bg);
+  border: 1px solid var(--vp-c-divider);
+  border-radius: 6px;
+  padding: 0.5rem 0.6rem;
+  opacity: 0.4;
+  transition: all 0.3s;
+}
+
+.pipeline-stage.active {
+  opacity: 1;
+  border-color: var(--vp-c-brand);
+}
+
+.stage-header {
+  display: flex;
+  align-items: center;
+  gap: 0.4rem;
+}
+
+.stage-num {
+  width: 1.2rem;
+  height: 1.2rem;
+  background: var(--vp-c-divider);
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 0.6rem;
+  font-weight: 600;
+  color: var(--vp-c-text-2);
+}
+
+.pipeline-stage.active .stage-num {
+  background: var(--vp-c-brand);
+  color: white;
+}
+
+.stage-name {
+  font-size: 0.75rem;
+  font-weight: 600;
+  color: var(--vp-c-text-2);
+}
+
+.stage-desc {
+  font-size: 0.68rem;
+  color: var(--vp-c-text-3);
+  margin-top: 0.15rem;
+}
+
+.stage-detail {
+  font-size: 0.65rem;
+  color: var(--vp-c-brand);
+  margin-top: 0.3rem;
+  padding: 0.25rem 0.4rem;
+  background: var(--vp-c-bg-soft);
+  border-radius: 4px;
+}
+
+.tap-hint {
+  text-align: center;
+  font-size: 0.72rem;
+  color: var(--vp-c-text-3);
+  margin-top: 0.75rem;
+}
+</style>