[BUG] Author field in `apm.yml` is not being properly filled due to unicode escaping

[alopezsanchez]

Describe the bug
When apm init (or apm install in zero-config mode) auto-detects the git user.name and writes the author field to apm.yml, non-ASCII characters are escaped as \xNN sequences instead of being written as proper UTF-8.

For example, a git user named Alejandro López Sánchez produces:

author: "Alejandro L\xF3pez S\xE1nchez"

This is caused by PyYAML's yaml.safe_dump() / yaml.dump() defaulting to allow_unicode=False, which forces ASCII-safe escaping regardless of file encoding.
The same issue affects any code path that re-writes apm.yml (install, uninstall, script runner), since round-tripping through PyYAML without allow_unicode=True will re-escape any non-ASCII content.

To Reproduce

1. Configure git with a non-ASCII name: git config user.name "Alejandro López Sánchez"
2. Run apm init --yes in a new directory
3. Open the generated apm.yml
4. The author field contains escaped sequences: "Pepe Rodríguez"

Expected behavior
The author field should contain the actual UTF-8 characters:

author: Alejandro López Sánchez

Environment (please complete the following information):

• OS: Any (reproduced on macOS)
• Python Version: 3.12
• APM Version: 0.8.3
• VSCode Version: N/A

Logs
No error is raised — the YAML is technically valid, but the human-readable content is garbled.