Add support for styleGuideIds in AI Translation methods

The Crowdin API exposes an optional `styleGuideIds` field on the **AI Translation** request bodies in both Crowdin and Crowdin Enterprise. It is an array of Style Guide identifiers used as context during AI translation. API client libraries should expose `styleGuideIds` on these requests so consumers can pass style guides via the SDK.

Affected endpoints:

- **AI Translate Strings** — `api.users.ai.translate.strings.post` (Enterprise: `api.ai.translate.strings.post`)
- **AI File Translation** — `api.users.ai.file-translations.post` (Enterprise: `api.ai.file-translations.post`)

**References:**
- [AI Translate Strings](https://support.crowdin.com/developer/api/v2/#tag/AI/operation/api.users.ai.translate.strings.post)
- [AI File Translation](https://support.crowdin.com/developer/api/v2/#tag/AI/operation/api.users.ai.file-translations.post)
- [List Style Guides](https://support.crowdin.com/developer/api/v2/#operation/api.style-guides.getMany)
- Crowdin Enterprise: [AI Translate Strings](https://support.crowdin.com/developer/enterprise/api/v2/#tag/AI/operation/api.ai.translate.strings.post), [AI File Translation](https://support.crowdin.com/developer/enterprise/api/v2/#tag/AI/operation/api.ai.file-translations.post)

Start by locating the request types and implementations behind api.users.ai.translate.strings.post, api.users.ai.file-translations.post, and their Enterprise api.ai equivalents. Check the linked Crowdin API references for the optional styleGuideIds array; the work is done when consumers can pass style guide identifiers to all four AI translation requests and the existing client behavior remains intact.

Written by the indexing model from the issue text.