Remove byteorder dependency and replace with built-in byte order methods

[sile]

No description provided.

[Copilot]

Pull Request Overview

This PR removes the external byteorder dependency and replaces it with custom built-in byte order methods. The change implements custom ReadExt and WriteExt traits that provide big-endian byte reading and writing methods using Rust's built-in from_be_bytes() and to_be_bytes() functions.

• Removes the byteorder crate dependency from Cargo.toml
• Replaces all byteorder::BigEndian method calls with custom trait methods
• Adds new ReadExt and WriteExt traits with big-endian byte conversion methods

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/codec.rs	Removes byteorder imports, updates all read/write calls to use custom methods, and implements new ReadExt/WriteExt traits
Cargo.toml	Removes byteorder dependency

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}