chore: refine package contents and add project badges

Author: Yunuuuu

Cargo.toml

@@ -10,6 +10,7 @@ readme = "README.md"
 repository = "https://github.com/WangLabCSU/decen"
 keywords = ["codec", "framing", "io", "buffer", "zero-copy"]
 categories = ["encoding"]
+exclude = ["/AGENTS.md", "/.github/", "/.gitignore", "/rust-toolchain.toml"]
 
 [dependencies]
 bytes = "1.12.*"

README.md

@@ -1,5 +1,10 @@
 # decen
 
+[<img alt="github" src="https://img.shields.io/badge/github-WangLabCSU/decen-8da0cb?style=for-the-badge&labelColor=555555&logo=github" height="20">](https://github.com/WangLabCSU/decen)
+[<img alt="crates.io" src="https://img.shields.io/crates/v/decen.svg?style=for-the-badge&color=fc8d62&logo=rust" height="20">](https://crates.io/crates/decen)
+[<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-decen-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs" height="20">](https://docs.rs/decen)
+[<img alt="build status" src="https://img.shields.io/github/actions/workflow/status/WangLabCSU/decen/ci.yml?branch=main&style=for-the-badge" height="20">](https://github.com/WangLabCSU/decen/actions?query=branch%3Amain)
+
 **decen** takes its name from **decoder** and **encoder**. It provides traits
 for defining frame boundaries, decoding frames, and encoding values, together
 with buffered readers and writers that use those implementations.