perf(plugin): optimize directory traversal by replacing filepath.Walk with filepath.WalkDir

[ankit98040]

Description

perf(plugin): optimize directory traversal with filepath.WalkDir

Prior to Go 1.16, filepath.Walk invoked os.Lstat on every visited file or directory to retrieve a heavy fs.FileInfo object, causing a significant performance bottleneck due to excessive system calls.

This commit replaces filepath.Walk with the more performant filepath.WalkDir API in the pkg/module package. The newer API passes an fs.DirEntry instead, which utilizes cached directory entry information provided by modern operating systems during the initial directory read.

This optimization minimizes unnecessary lstat syscalls over large directory structures when loading WebAssembly modules, significantly improving filesystem traversal speed and reducing CPU overhead.

Checklist

• I've read the guidelines for contributing to this repository.
• I've followed the conventions in the PR title.
• I've added tests that prove my fix is effective or that my feature works.
• I've updated the documentation with the relevant information (if needed).
• I've added usage information (if the PR introduces new options)
• I've included a "before" and "after" example to the description (if the PR is a user interface change).

[knqyf263]

Thanks for your contribution. While the practical performance gain may be minimal since the WASM module directory typically doesn't contain a large number of files, there's no downside to this change. filepath.WalkDir is the recommended API since Go 1.16.