- Add 8 new test functions: printers_new_returns_200, create_printer_redirects,
printers_library_no_form, patch_printer, patch_printer_not_found,
client_detail_returns_200, client_detail_not_found, client_links_in_printer_list
- Add FIXME comments on existing POST /printers tests noting upcoming 303 change
- All new tests FAIL against current code (proper RED TDD state)
- Existing 13 tests remain GREEN