Remove github.com/mitchellh/go-homedir in favor of stdlib
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### Checklist
<!-- Please test the latest versions, that will remove the possibility that you see a bug that is fixed in a newer version. -->
- [x] I'm using the latest version of the extension (Run `glab --version`)
- [x] Operating system and version: Fedora
### Summary
<!-- Summarize the bug encountered concisely -->
Remove the direct dependency on deprecated `github.com/mitchellh/go-homedir` and use `os.UserHomeDir()` from the standard library for resolving the user home directory when parsing SSH config (including `~/.ssh/config` and tilde expansion in `Include` paths). No intentional user-facing behavior change.
### What is the current _bug_ behavior?
<!-- What actually happens -->
The CLI module still depended on `mitchellh/go-homedir`, which is deprecated; the same need is covered by `os.UserHomeDir()` in the standard library.
### What is the expected _correct_ behavior?
<!-- What you should see instead -->
No direct dependency on `go-homedir`; home directory resolution for SSH config continues to work as today.
### Relevant logs and/or screenshots
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### Possible fixes
<!-- If you can, link to the line of code that might be responsible for the problem -->
Replace `homedir.Dir()` with `os.UserHomeDir()` in SSH config parsing and run `go mod tidy`.
Will attach a MR.
issue