* feat: add error message if org doesn't own stock * feat: move org relationship errors to model * feat: use correct model for form * tests: update params in tests * feat: add specific fields for parent/child errors * test: fix params in failing tests * refactor: unrelated linting * feat: simplify controller behaviour further * test: address failing tests * feat: add copy to en.yml * feat: add updated validation message and rename related housing provider -> stock owner