feat: add homebrew-php plugin

[naviapis]

Summary

Description:

Re-submission of the plugin entry proposed in #1129.
The original PR was automatically closed when my fork was deleted.

This plugin provides Homebrew-based PHP version switching for asdf and mise on macOS.
It is intended for environments where Homebrew PHP is already standard, offering a simple alternative to source-build PHP plugins, which can behave less predictably on macOS due to frequent Homebrew dependency changes.

• Tool repo URL: https://github.com/naviapps/asdf-homebrew-php
• Plugin repo URL: https://github.com/naviapps/asdf-homebrew-php

Checklist

• Format with scripts/format.bash
• Test locally with scripts/test_plugin.bash --file plugins/<your_new_plugin_name>
• Your plugin CI tests are green
  • Tip: use the plugin_test action from asdf-actions in your plugin CI