The roster builder's seven-day flag looks inside one Monday-to-Sunday week. A person who works Thursday to Sunday and then Monday to Wednesday has worked seven days in a row, and no single week shows it. --weeks now joins a Sunday shift to the next Monday and reports any run longer than six days (planStreaks in ventures/shift-roster-builder/calc.mjs).
It is a report, not a limit: the search does not avoid such runs, and it knows nothing about days worked before the first planned week. The test uses a hand-built two-week plan, not a real payroll, and what a run of days costs depends on your state's rule, which the tool does not model.