Add support for task batches (batchId) and the consolidated vendor task form

The Crowdin API updates the **Tasks** resource with task-batch support and a reworked vendor task creation form. API client libraries should be updated accordingly.

**Task batches (`batchId`) — Crowdin and Crowdin Enterprise:**

- **List Tasks** (`api.projects.tasks.getMany`) gains a new optional `batchId` query parameter to filter tasks by batch.
- **Add Task** (`api.projects.tasks.post`) gains a new optional `batchId` field on the create forms to group tasks into a batch.
- **Edit Task** (`api.projects.tasks.patch`) allows editing `batchId` (and `resetScope`).

**Vendor task form consolidation — Crowdin only (breaking):**

The per-vendor create forms (`CrowdinLanguageServiceTaskCreateForm`, `CrowdinVendorOhtTaskCreateForm`, `CrowdinVendorGengoTaskCreateForm`, `CrowdinVendorManualTaskCreateForm`, `CrowdinVendorManualPendingTaskCreateForm`) are removed and replaced by a single generic `CrowdinVendorTaskCreateForm`, where `vendor` is a free-form vendor identifier from the Crowdin Store. New fields `skipAssignedStrings` and `deadline` are added; vendor-specific fields such as `expertise` and `editService` are removed. The **Add Task** request body `oneOf` is updated to reference the new forms. Clients that model the vendor task variants explicitly must update their request types.

**References:**
- [List Tasks](https://support.crowdin.com/developer/api/v2/#operation/api.projects.tasks.getMany)
- [Add Task](https://support.crowdin.com/developer/api/v2/#operation/api.projects.tasks.post)
- [Edit Task](https://support.crowdin.com/developer/api/v2/#operation/api.projects.tasks.patch)
- Crowdin Enterprise (`batchId` only): [List Tasks](https://support.crowdin.com/developer/enterprise/api/v2/#operation/api.projects.tasks.getMany), [Add Task](https://support.crowdin.com/developer/enterprise/api/v2/#operation/api.projects.tasks.post), [Edit Task](https://support.crowdin.com/developer/enterprise/api/v2/#operation/api.projects.tasks.patch)

Start with the api.projects.tasks.getMany, api.projects.tasks.post, and api.projects.tasks.patch entry points and locate their task request and form types. Compare those types with the Crowdin and Crowdin Enterprise API references, then update batchId and the consolidated vendor form, including the Add Task oneOf; done means both API variants model the documented fields and removed forms correctly.

Written by the indexing model from the issue text.