refactor(bench): optimize buffer initialization

- Introduce static state pattern with lazy initialization
- Eliminate redundant buffer reinitializations in benchmarks
- Use compile-time buffer size constants
- Update CI workflow badge reference in documentation

Author: jinzhongjia

README.md

@@ -1,6 +1,6 @@
 # zig-msgpack
 
-[![CI](https://github.com/zigcc/zig-msgpack/actions/workflows/ci.yml/badge.svg)](https://github.com/zigcc/zig-msgpack/actions/workflows/ci.yml)
+[![CI](https://github.com/zigcc/zig-msgpack/actions/workflows/test.yml/badge.svg)](https://github.com/zigcc/zig-msgpack/actions/workflows/test.yml)
 
 A MessagePack implementation for the Zig programming language. This library provides a simple and efficient way to serialize and deserialize data using the MessagePack format.
 

README_CN.md

@@ -1,6 +1,6 @@
 # zig-msgpack
 
-[![CI](https://github.com/zigcc/zig-msgpack/actions/workflows/ci.yml/badge.svg)](https://github.com/zigcc/zig-msgpack/actions/workflows/ci.yml)
+[![CI](https://github.com/zigcc/zig-msgpack/actions/workflows/test.yml/badge.svg)](https://github.com/zigcc/zig-msgpack/actions/workflows/test.yml)
 
 Zig 编程语言的 MessagePack 实现。此库提供了一种简单高效的方式来使用 MessagePack 格式序列化和反序列化数据。