Add Asset bulk-assign method

[evanvolgas]

Summary

The SDK is missing the bulk-assign endpoint for reassigning asset ownership.

Core API endpoint

• POST /assets/bulk-assign - Reassign multiple assets to a new team/user

Method to add

class AssetsResource:
    def bulk_assign(
        self,
        asset_ids: list[UUID],
        owner_team_id: UUID | None = None,
        owner_user_id: UUID | None = None
    ) -> BulkAssignResponse:
        """Reassign ownership of multiple assets at once."""

class BulkAssignResponse(BaseModel):
    updated: int
    asset_ids: list[UUID]

Use case

Org restructuring - moving assets between teams in bulk.