Upserts a batch of tags in the caller's tenant in a single transaction:

• a record without id creates a new tag and publishes a tag-created domain event (ETagCreatedEvent);
• a record with id updates the label and active flag of that existing tag (no event is published for updates).

Tags not mentioned in the request are left untouched — this is not a full replace, and tags cannot be deleted through this operation (use DELETE /tags/{tagId}). The response contains only the created/updated tags, in request order.

Authorization: requires the global:metadata:manage scope.

Errors (400): empty tags list; the same label used twice in one request; a blank label or a label longer than 255 characters; missing active; an id that does not exist in the tenant; a concurrent modification of the same tag. Duplicate labels are only checked within the request, not against tags that already exist. Any error rolls back the whole batch.