Handle additional git providers in set_composer_auth_env_var()

[Copilot]

Plan: Add support for additional git providers in set_composer_auth_env_var()

• Review current implementation of set_composer_auth_env_var()
• Add support for bitbucket-oauth via BITBUCKET_CONSUMER_KEY and BITBUCKET_CONSUMER_SECRET environment variables
• Add support for gitlab-oauth via GITLAB_OAUTH_TOKEN environment variable
• Add support for gitlab-token via GITLAB_TOKEN environment variable
• Add support for http-basic via HTTP_BASIC_AUTH environment variable (JSON format)
• Add comprehensive PHPUnit unit tests to validate all authentication providers
• Refactor tests to reduce code duplication with helper method
• Add Behat feature tests for the authentication functionality
• Add empty string validation for all token environment variables
• Run lint, phpcs, phpstan to ensure code quality (all passed)
• Run PHPUnit test suite - all 86 tests passed
• All changes complete and verified

Security Summary

✅ No security vulnerabilities detected

• CodeQL analysis found no security issues in the changes
• All authentication tokens are handled securely via environment variables
• Empty strings are rejected to prevent empty credentials in COMPOSER_AUTH
• Existing COMPOSER_AUTH values are preserved and never overridden
• Invalid JSON in HTTP_BASIC_AUTH is safely ignored
• All environment variables are validated before use
• No sensitive data is logged or exposed

Original prompt

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This section details on the original issue you should resolve

<issue_title>Handle more git providers in set_composer_auth_env_var()</issue_title>
<issue_description>As of #47, we support GitHub. There are a few other providers we could support too:

• bitbucket-oauth
• gitlab-oauth
• gitlab-token
• http-basic</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Handle more git providers in set_composer_auth_env_var() #48

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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