Email validation rejects valid addresses with hyphenated domain labels #360

Prerequisites

• Checked that your issue isn't already filed
• Tried upgrading to the latest git-mob version (npm i -g git-mob)
• Tried upgrading to the latest git version (brew upgrade git if installed with Homebrew/Linuxbrew)

Description

git add-coauthor rejects valid email addresses whose domain labels contain hyphens (e.g., kyushu-u.ac.jp, example-corp.com) with the error Invalid email format..
Hyphens in domain labels are allowed by RFC 1035 2.3.1, so these addresses should be accepted.

Steps to Reproduce

1. Run git add-coauthor tu "Test User" user@kyushu-u.ac.jp
2. Observe the error message

Expected behavior: The coauthor with the hyphenated domain email is added to .git-coauthors.

Actual behavior: The command fails with Invalid email format. and nothing is written to .git-coauthors.

Reproduces how often: 100%

Versions

• operating system and version: macOS Tahoe 26.4
• git-mob version (git-mob --version): 4.0.1
• git version (git --version): 2.53.0

Additional Information

The validateEmail function in packages/git-mob/src/helpers.ts uses the regex (\w+\.)+[a-zA-Z]{2,} for the domain portion of an email address.
JavaScript's \w is [A-Za-z0-9_] and does not include -, so this pattern fails to match any label that contains a hyphen.

I work around this by registering with a dummy address (e.g., xxx@gmail.com) and then manually editing .git-coauthors (path: git mob -p) to replace it with the actual address.

Suggested fix (accepts - and rejects _ in the domain part, since _ is not valid in DNS labels per RFC 1035):

- /^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[(?:\d{1,3}\.){3}\d{1,3}])|((\w+\.)+[a-zA-Z]{2,}))$/
+ /^(([^<>()[\]\\.,;:\s@"]+(\.[^<>()[\]\\.,;:\s@"]+)*)|(".+"))@((\[(?:\d{1,3}\.){3}\d{1,3}])|(([A-Za-z0-9-]+\.)+[A-Za-z]{2,}))$/