Stdlib: msgpack_pack/msgpack_unpack PHP implementation (#6551)

[PurHur]

Summary

Implements ext/msgpack msgpack_pack() / msgpack_unpack() as pure PHP (php-src ext/msgpack/msgpack.c reference). Replaces the phantom module stub that kept function_exists('msgpack_*') false.

• ext/msgpack/VmMsgpack.php — MessagePack encode/decode for null/bool/int/float/string/array/map
• Register msgpack_pack / msgpack_unpack on the msgpack extension module
• Compliance + unit guards; maintainer repro updated from phantom-false to round-trip ok

Verification

./script/docker-exec.sh -- bash -lc 'source script/php-env.sh
php bin/vm.php test/repro-maintainer/parity_msgpack_roundtrip.php
# ok
php bin/vm.php test/repro/maintainer_gap_msgpack_phantom_registration.php
# ok
vendor/bin/phpunit test/unit/MsgpackModuleTest.php --no-configuration
# OK (2 tests, 4 assertions)
php script/bootstrap-inventory.php --check
# OK 4482/4482
'

Closes #6551

Made with Cursor