feat: support asymmetric visibility in constructor promotion

[hbtweb]

Summary

PHP 8.4 added asymmetric visibility which allows separate read/write visibility on properties. PR #258 added support for this on property declarations, but missed the case where two visibility modifiers are used in constructor promotion parameters.

This PR adds an optional set_visibility field to property_promotion_parameter so that constructs like this parse correctly:

class User {
    public function __construct(
        public private(set) string $name,
        public protected(set) int $age,
    ) {}
}

Before: private(set) / protected(set) in constructor promotion with a preceding visibility modifier produces a parse error.

After: Parsed correctly as two visibility_modifier nodes — one for read, one for write.

Changes

• common/define-grammar.js: Added optional set_visibility field to property_promotion_parameter
• test/corpus/class.txt: Added test case for asymmetric visibility in constructor promotion
• php/src/parser.c: Regenerated

Test plan

• All 144 existing tests pass (0 failures)
• New test case "Asymmetric Visibility in Constructor Promotion" passes
• Existing "Asymmetric Property Visibility" test still passes
• Single visibility modifier in constructor promotion still works (private(set) string $title)

[calebdw]

Thanks! I changed it from set_visibility to just repeating the visibility field---if you only have private(set) then it would be parsed as the visibility field and not the set_visibility field which is not correct.

I also regenerated the grammar (make generate)