Stdlib: extract() and compact() for template includes (#275)

[PurHur]

Summary

• Implement extract() and compact() on the VM path for string-keyed arrays and literal compact() name lists.
• Link the caller Frame when invoking internal builtins so scope import targets the correct compiled locals.
• Add compliance PHPT coverage (extract_compact, extract_skip) and register builtins in ext/standard/Module.php.

JIT / AOT

JIT lowering is not enabled yet (not implemented for JIT); JITTest skips the new PHPT cases until LLVM scope import is stable (follow-up on #275). VM acceptance matches the issue:

docker run --rm -v "$(pwd):/compiler" -w /compiler php-compiler:22.04-dev \
  bash -c 'echo "<?php \$t=[\"name\"=>\"Dev\"]; extract(\$t); echo \$name;" | php bin/vm.php'
# Dev

Test plan

• script/ci-local.sh VM/compliance slice (195 VM PHPT cases OK)
• Manual bin/vm.php extract smoke
• JIT extract/compact (tracked in Stdlib: extract() and compact() for PHP template includes #275)

Closes #275

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