Class-level template substitution doesn't propagate to parameter types in type error checker

[AJenbo]

PHPantom version

main

Installation method

Built from source

Operating system

Linux x86_64

Editor

Zed

Bug description

When a generic class like HasMany<TRelatedModel, TDeclaringModel>
has a method with @param TRelatedModel $model, and the class is
instantiated with concrete type arguments (e.g.
HasMany<Translation, Tag>), the type error checker does not
substitute TRelatedModel → Translation in the parameter type.
The diagnostic sees "expects TRelatedModel, got Translation" and
fires a false positive.

The completion/hover pipeline already performs class-level template
substitution via build_substitution_map in inheritance.rs, but
the type error diagnostic collector does not apply the same
substitution when comparing argument types against parameter types
on generic class methods.

Reproducer:

/**
 * @template TRelatedModel
 * @template TDeclaringModel
 */
class HasMany {
    /** @param TRelatedModel $model */
    public function save($model): void {}
}

class Translation {}
class Tag {
    /** @return HasMany<Translation, Tag> */
    public function translations(): HasMany { return new HasMany(); }
}

function test(): void {
    $tag = new Tag();
    $translation = new Translation();
    $tag->translations()->save($translation);
    // false positive: "expects TRelatedModel, got Translation"
}

Steps to reproduce

Run diagnostics

Error output or panic trace

.phpantom.toml

Additional context

No response