FormulaFence 0.220.0

Workbook serial-date-system controls\n\n- Adds high-severity FF117 when normalized workbook date1904 or dateCompatibility controls change, with safe public details.\n- Adds no_workbook_date_system_changes, producing FFP117 for CI enforcement.\n- Profiles expose the normalized date controls, whether date compatibility was explicitly declared, and coverage gaps without calculating formulas, converting serials, or predicting client display.\n- Normalizes OOXML defaults: omitted date1904 is false and omitted dateCompatibility is true.\n- The narrow XLSB profile now exposes its core date-1904 bit while retaining its explicit non-core coverage boundary.\n\nValidation: 1,589 tests passed; Ruff, compile checks, package metadata checks, and fresh wheel/source-distribution installs passed.