fix(php): capture interface/enum/trait heritage as class-like nodes

[Synvoya]

Bug

PHP interfaces, enums, and traits produce no node and no heritage edges. interface B extends A, enum E implements I, and trait T { use U; } are all silently dropped.

Root cause

_PHP_CONFIG.class_types only contained class_declaration, so the generic extractor never treated interface_declaration, enum_declaration, or trait_declaration nodes as class-like. They never became nodes, and the PHP heritage handler (which runs per class-like node) never fired for them.

Minimal repro

<?php
interface Identifiable {}
interface Nameable extends Identifiable {}
enum Suit: string implements Nameable {
    case Hearts = 'H';
    public function label(): string { return 'x'; }
}
trait Named {}
trait Greets { use Named; }

Before: no Nameable/Suit/Greets nodes, no inherits/implements/mixes_in edges.

Fix

• Add interface_declaration, enum_declaration, and trait_declaration to _PHP_CONFIG.class_types.
• Enums wrap members in an enum_declaration_list (not a declaration_list), so add it to body_fallback_child_types so enum methods/cases are walked.

After the fix the repro yields:

• Nameable --inherits--> Identifiable
• Suit --implements--> Nameable
• Greets --mixes_in--> Named
• Suit --method--> label (enum body now walked)

Testing

• Added test_php_interface_enum_trait_heritage to tests/test_languages.py, mirroring the existing test_php_splits_inherits_implements_mixes_in assertion style. Fails before, passes after.
• tests/test_languages.py: 315 passed, 13 skipped (was 314 + this new test).

[Lautaroscu]

good job