- twelve-month tests use hard-coded, independently verified (month,
first, second, third, fourth, last) fixtures with weekday assertions
- n=5 tests assert exact hit months {3, 6, 8, 11}, that each hit is the
month's FINAL Monday (no later Monday fires, prior Monday doesn't),
and four-occurrence months never fire on any day
- helper last() facts corrected: Feb 2028 last Saturday is the 26th
(Feb 29 is a Tuesday), verified via plain datetime arithmetic
- March 1 2026 corrected to Sunday; weekday-code naming fixed
(2 = Wednesday)
Joshua King