fix(services): handle trailing slash

[Isvane]

Motivation

Hi. This is my first time contributing to global library and I wanted to help out with #654.

The goal here was to make sure that if someone tries to access a file with a trailing slash (like /index.html/), the server doesn't get confused and try to serve it as a file. It should only allow the trailing slash if it’s actually a directory.

Solution

• In serve_dir/mod.rs, I added a check to see if the requested URI ends with a /.
• I passed that info into the open_file function.
• Inside open_file.rs, I added a check: if there’s a trailing slash but the metadata says "this is a file," we return FileNotFound.
• I added a new test case in tests.rs to make sure requesting /index.html/ now correctly returns a 404.

I'm very open to feedback if there’s a cleaner way to handle this or if I missed any project conventions, please let me know.