add packagist support

[xHeaven]

This PR adds support for PHP packages via Packagist.
It adds 3 aliases: packagist, composer and php

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[ctate]

Nice work - this is well-structured and follows the existing patterns cleanly

Two small fixes before merging:

1. Remove the unused includeDev parameter from getAvailableVersions (line 143 in packagist.ts) - it's defined but never used.

2. Add Bitbucket git URL normalization in extractRepoUrl:

.replace(/^git@bitbucket\.org:/, "https://bitbucket.org/")

You already handle GitHub and GitLab, just missing this one.

[xHeaven]

Nice work - this is well-structured and follows the existing patterns cleanly

Two small fixes before merging:

1. Remove the unused includeDev parameter from `getAvailableVersions` (line 143 in packagist.ts) - it's defined but never used.

2. Add Bitbucket git URL normalization in extractRepoUrl:

.replace(/^git@bitbucket\.org:/, "https://bitbucket.org/")

You already handle GitHub and GitLab, just missing this one.

I'll take a look at this, thanks!