docs: rewrite README with library catalog, community info, and descriptor guide (#10)

Author: Sunrisepeak

README.md

@@ -1,25 +1,129 @@
 # mcpp-index
 
-> Default package registry for [`mcpp`](https://github.com/mcpp-community/mcpp).
-> Browse: **https://mcpp-community.github.io/mcpp-index/**
+> [`mcpp`](https://github.com/mcpp-community/mcpp) 构建工具的默认包索引仓库
+>
+> 在线浏览: **https://mcpplibs.github.io/mcpp-index/**
+
+## 快速使用
 
 ```bash
-mcpp add mcpplibs.cmdline@0.0.2     # → updates mcpp.toml
-mcpp build                            # → fetches sources, builds
+mcpp add ftxui@6.1.9       # 添加依赖到 mcpp.toml
+mcpp build                  # 自动拉取源码 + 构建
+```
+
+## 已收录的包
+
+### mcpplibs 模块化库
+
+| 包名 | 版本 | 简介 | 仓库 |
+|------|------|------|------|
+| `mcpplibs.cmdline` | 0.0.2 | 命令行解析框架 — `import mcpplibs.cmdline;` | [mcpplibs/cmdline](https://github.com/mcpplibs/cmdline) |
+| `mcpplibs.tinyhttps` | 0.2.2 | 轻量 HTTP/HTTPS 客户端(SSE 流式) — `import mcpplibs.tinyhttps;` | [mcpplibs/tinyhttps](https://github.com/mcpplibs/tinyhttps) |
+| `mcpplibs.llmapi` | 0.2.5 | 大语言模型 API 客户端(OpenAI/Anthropic 兼容) — `import mcpplibs.llmapi;` | [mcpplibs/llmapi](https://github.com/mcpplibs/llmapi) |
+| `mcpplibs.capi.lua` | 0.0.3 | Lua 5.4 C API 的 C++23 模块封装 — `import mcpplibs.capi.lua;` | [mcpplibs/lua](https://github.com/mcpplibs/lua) |
+| `mcpplibs.xpkg` | 0.0.39 | xpkg V1 规范的 C++23 参考实现 — `import mcpplibs.xpkg;` | [openxlings/libxpkg](https://github.com/openxlings/libxpkg) |
+| `mcpplibs.templates` | 0.0.1 | 最小化模块库模板 — `import mcpplibs.templates;` | [mcpplibs/templates](https://github.com/mcpplibs/templates) |
+
+### 第三方 C/C++ 库
+
+| 包名 | 版本 | 简介 |
+|------|------|------|
+| `ftxui` | 6.1.9 | C++ 函数式终端 UI 库(screen + dom + component) |
+| `gtest` | 1.15.2 | Google Test 测试框架 |
+| `mbedtls` | 3.6.1 | TLS/加密库(纯 C) |
+| `lua` | 5.4.7 | Lua 脚本语言(纯 C 嵌入式库) |
+
+### 依赖关系链
+
+```
+mcpplibs.llmapi
+  └── mcpplibs.tinyhttps
+        └── mbedtls              ← mcpp 自动传递,无需手动声明
+
+mcpplibs.xpkg
+  └── mcpplibs.capi.lua
+        └── lua                  ← 同上
+```
+
+mcpp 0.0.3+ 的 transitive walker 自动沿链路传播头文件和依赖,消费者只需声明直接依赖。
+
+## 包描述文件
+
+每个包对应一个 `pkgs/<首字母>/<包名>.lua` 文件,遵循 [xpkg V1 规范](https://github.com/d2learn/xim-pkgindex/blob/main/docs/V1/xpackage-spec.md)。
+
+### 两种形式
+
+**Form A** — 上游自带 `mcpp.toml`,描述文件只声明元数据和下载地址:
+
+```lua
+package = {
+    spec = "1",
+    name = "mcpplibs.tinyhttps",
+    xpm = {
+        linux   = { ["0.2.2"] = { url = "...", sha256 = "..." } },
+        macosx  = { ["0.2.2"] = { url = "...", sha256 = "..." } },
+        windows = { ["0.2.2"] = { url = "...", sha256 = "..." } },
+    },
+}
 ```
 
-## Adding a package
+**Form B** — 上游没有 `mcpp.toml`,在描述文件里内联构建信息:
+
+```lua
+package = {
+    spec = "1",
+    name = "ftxui",
+    xpm = { ... },
+    mcpp = {
+        include_dirs = { "*/include", "*/src" },
+        sources = {
+            "*/src/ftxui/**/*.cpp",
+            "!*/src/ftxui/**/*_test.cpp",      -- glob 排除(mcpp 0.0.4+)
+            "!*/src/ftxui/**/*_fuzzer.cpp",
+        },
+        targets = { ["ftxui"] = { kind = "lib" } },
+    },
+}
+```
+
+### 获取方式
+
+mcpp 初次运行时自动 clone 本仓库到 `~/.mcpp/registry/data/mcpp-index/`。后续更新:
+
+```bash
+mcpp search <keyword>    # 触发索引刷新 + 搜索
+```
+
+也可手动拉取:
+
+```bash
+cd ~/.mcpp/registry/data/mcpp-index && git pull
+```
+
+## 添加新包
+
+1. Fork 本仓库
+2. 在 `pkgs/<首字母>/` 下创建 `<包名>.lua`,参考现有文件([mbedtls.lua](pkgs/m/mbedtls.lua)、[ftxui.lua](pkgs/f/ftxui.lua))
+3. 提交 PR — `validate` workflow 自动 lint,`deploy-site` 合入后自动发布到浏览站
+
+详细格式说明见 [mcpp 扩展字段文档](https://github.com/mcpp-community/mcpp/blob/main/docs/04-schema-xpkg-extension.md)。
+
+## 相关链接
+
+| 项目 | 说明 |
+|------|------|
+| [mcpp](https://github.com/mcpp-community/mcpp) | 现代 C++23 构建 & 包管理工具 |
+| [xlings](https://github.com/d2learn/xlings) | mcpp 底层的包安装引擎 + 沙箱环境 |
+| [xpkg V1 spec](https://github.com/d2learn/xim-pkgindex/blob/main/docs/V1/xpackage-spec.md) | 包描述文件规范 |
+| [mcpplibs](https://github.com/mcpplibs) | mcpp 生态的模块化 C++23 库集合 |
+| [xim-pkgindex](https://github.com/d2learn/xim-pkgindex) | xlings 的通用包索引仓库 |
+
+## 社区
 
-Drop one [xpkg V1](https://github.com/d2learn/xim-pkgindex/blob/main/docs/V1/xpackage-spec.md)
-descriptor at `pkgs/<first-letter>/<name>.lua`. Existing files (e.g.
-[`pkgs/m/mbedtls.lua`](pkgs/m/mbedtls.lua),
-[`pkgs/l/lua.lua`](pkgs/l/lua.lua)) are the canonical templates;
-the [mcpp extension](https://github.com/mcpp-community/mcpp/blob/main/docs/04-schema-xpkg-extension.md)
-covers the optional `mcpp = { ... }` segment for upstreams that
-don't ship their own `mcpp.toml`. Open a PR — the `validate`
-workflow lint-checks descriptors, the `deploy-site` workflow
-republishes the browse site after merge.
+- **Issues / 反馈**: [mcpp issues](https://github.com/mcpp-community/mcpp/issues) · [mcpp-index issues](https://github.com/mcpp-community/mcpp-index/issues)
+- **讨论 / 论坛**: [d2learn 论坛](https://forum.d2learn.org)
+- **mcpplibs 库贡献**: 各库仓库接受 PR,CI 使用 mcpp 构建验证
 
 ## License
 
-Descriptors: CC0. Each indexed upstream keeps its own license.
+包描述文件: CC0。各上游库保留其自身许可证。