Attachment content IDs are cast to 0 during hydration

[virtualLast]

Description

After introducing the additional hydration for attachments (see #18 ), I have noted that Confluence Cloud returns attachment content IDs as prefixed strings, for example:

{
    "id": "att884637698",
    "type": "attachment"
}

However, AbstractContent::load() currently casts all content IDs to integers:

$content->setId((int) $data['id']);

and AbstractContent::$id is typed as ?int.

As a result, attachment IDs such as:

att884637698

are hydrated as:

0
Example

A request to:

GET /content/{pageId}/child/attachment

returns an attachment payload containing:

{
"id": "att884637698",
"type": "attachment",
"title": "example.jpg",
"_links": {
"self": "https://example.atlassian.net/wiki/rest/api/content/att884637698"
}
}

After hydration:

$attachment->getId();

returns:

0
Expected behaviour

The original attachment ID should be preserved:

$attachment->getId() === 'att884637698';

Possible fix

Widen the content ID type from int to int|string:

private int|string|null $id = null;

public function getId(): int|string|null
{
    return $this->id;
}

public function setId(int|string $id): self
{
    $this->id = $id;

    return $this;
}

Then hydrate the ID without casting:

$content->setId($data['id']);
This would preserve existing numeric page IDs while also supporting string attachment IDs.

I'm happy to knock out a PR for the above - just let me know if you're happy