Fix 204 responses still including a content schema

[TZK-]

Problem

Responses documented with status 204 still get a full content schema in the generated OpenAPI spec, instead of the expected empty response.

#[ResponseFromApiResource(BookResource::class, Book::class, 204)]
// or
#[Response(status: 204)]
public function destroy(Book $book)
{
    $book->delete();

    return response()->noContent();
}

Generated openapi.yaml (current, incorrect):

responses:
  204:
    description: ''
    content:
      application/json:
        schema:
          type: object
          properties:
            id: { type: integer, example: 1 }
            title: { type: string, example: 'Some title' }
            # ...the whole resource/model, or a generic {type: object, nullable: true}

Expected (per the OpenAPI spec, a 204 response has no body):

responses:
  204:
    description: ''

Root cause

In BaseGenerator::generateEndpointResponsesSpec():

$code = $response->status; // OpenAPI spec requires status codes to be integers
if ($code === '204') {
    // Must not add content for 204
    ...
}

Knuckles\Camel\Extraction\Response::$status is declared as a strictly-typed int (and is cast with (int) in its constructor), so $code is always an int. Comparing it with === against the string '204' is therefore always false.

Note

This branch also includes an unrelated one-line commit removing an unused import in src/Extracting/ParamHelpers.php. It was failing my branch's CI. Happy to drop it from this PR if you'd rather handle it separately.