docs: add Chinese architecture translation and fix VitePress config

- Create docs/zh/guide/architecture.md (translation of English version)
- Add architecture.md to both English and Chinese sidebars
- Fix og-image extension from .png to .svg (matching actual file)

Author: LessUp

docs/.vitepress/config.mts

@@ -8,6 +8,7 @@ const sharedSidebar = {
       items: [
         { text: 'Introduction', link: '/en/' },
         { text: 'Quick Start', link: '/en/guide/getting-started' },
+        { text: 'Architecture', link: '/en/guide/architecture' },
         { text: 'Project Structure', link: '/en/guide/project-structure' },
       ],
     },
@@ -53,6 +54,7 @@ const sharedSidebar = {
       items: [
         { text: '项目介绍', link: '/zh/' },
         { text: '快速开始', link: '/zh/guide/getting-started' },
+        { text: '架构设计', link: '/zh/guide/architecture' },
         { text: '项目结构', link: '/zh/guide/project-structure' },
       ],
     },
@@ -162,7 +164,7 @@ export default defineConfig({
     ['meta', { property: 'og:description', content: 'Classic lossless compression algorithms in C++17, Go, and Rust with cross-language binary verification.' }],
     ['meta', { property: 'og:url', content: 'https://lessup.github.io/compress-kit/' }],
     ['meta', { property: 'og:site_name', content: 'CompressKit' }],
-    ['meta', { property: 'og:image', content: '/compress-kit/og-image.png' }],
+    ['meta', { property: 'og:image', content: '/compress-kit/og-image.svg' }],
     ['meta', { property: 'og:image:width', content: '1200' }],
     ['meta', { property: 'og:image:height', content: '630' }],
 
@@ -171,7 +173,7 @@ export default defineConfig({
     ['meta', { name: 'twitter:site', content: '@compresskit' }],
     ['meta', { name: 'twitter:title', content: 'CompressKit | Compression Algorithms Collection' }],
     ['meta', { name: 'twitter:description', content: 'Classic lossless compression algorithms in C++17, Go, and Rust with cross-language binary verification.' }],
-    ['meta', { name: 'twitter:image', content: '/compress-kit/og-image.png' }],
+    ['meta', { name: 'twitter:image', content: '/compress-kit/og-image.svg' }],
 
     // Favicon
     ['link', { rel: 'icon', type: 'image/svg+xml', href: '/compress-kit/logo.svg' }],

docs/zh/guide/architecture.md

@@ -0,0 +1,31 @@
+# 架构设计
+
+CompressKit 现有算法核心之上采用两层内存集成模型：
+
+```text
+调用方
+  -> 缓冲层 (encode_buffer / decode_buffer)
+  -> 流式层 (process / flush / finish / reset)
+  -> 现有算法核心
+```
+
+## 设计目的
+
+- 文件到文件 CLI 现在与内存调用方共享相同的缓冲层路径
+- 生命周期语义在 C++17、Go 和 Rust 之间保持一致
+- 统一的错误处理使后续帧格式和一致性工作更易构建
+
+## 语言实现
+
+- C++: `algorithms/shared/cpp`
+- Go: `algorithms/shared/go`
+- Rust: `algorithms/shared/rust`
+
+## 安全边界
+
+- 流式层接受的输入上限为 `4 GiB`
+- 流式层产生的解码输出上限为 `1 GiB`
+
+## 验证
+
+`make test` 在运行算法特定测试套件之前，包含所有三种语言的共享流式生命周期测试。