Integrate CreateScalingGroup Action with existing GraphQL implementation

[jopemachine]

Objective

Complete Create action with GraphQL integration and comprehensive tests.

Implementation Details

• GraphQL mutation modification (~30 lines)
  • CreateScalingGroupInput → Creator conversion logic
  • simple_db_mutate_returning_item → processors.scaling_group.create.wait_for_complete()
• ScalingGroupOpts conversion logic cleanup (~20 lines)
• Additional Unit tests:
  • test_create_scaling_group_service.py (~80 lines)
  • test_create_scaling_group_repository.py (~100 lines)
• Edge case tests (duplicate name, validation, etc.) (~50 lines)

Estimated Lines

~280 lines

Dependencies

• Story 3: CreateScalingGroup Action - Creator Spec

Acceptance Criteria

• [ ] GraphQL mutation uses new processor pattern
• [ ] Input conversion properly handles all fields including ScalingGroupOpts
• [ ] Edge cases tested (duplicate names, invalid inputs)
• [ ] All unit tests pass
• [ ] Legacy simple_db_mutate_returning_item removed from CreateScalingGroup

JIRA Issue: BA-3485