calendar: split privileged-feria into two real precedence tiers

A plain Duplex saint was losing to any privileged feria (Ember days
included) since the occurrence engine only let duplex-1-classis+ get
even a commemoration there. Verified this was wrong: St. Gregory the
Great, plain Duplex, outright wins against a Lenten Ember Saturday in
the real Monastic 1617 engine.

Splits TemporalCategory's single privileged-feria into privileged-feria
(the lesser tier — Lent's Ember days, verified — now behaves like an
ordinary Sunday: Duplex+ wins outright) and privileged-feria-major (Ash
Wednesday, Holy Week, the Easter Octave, verified via St. Mark only ever
being commemorated there, never winning — behaves like privileged-
Sunday). Everywhere else the old single category was ambiguous
(Pentecost's own Ember days/Vigil/Octave, the Vigil of Christmas)
defaults to the stricter major tier pending verification.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/calendar/vespers.ts

@@ -42,7 +42,12 @@ function hasFirstVespers(day: LiturgicalDay): boolean {
 
 /** Does this day keep its own Second Vespers regardless of what tomorrow is? */
 function keepsOwnSecondVespers(day: LiturgicalDay): boolean {
-  if (day.weekday === 'sunday' || day.temporalCategory === 'privileged-feria' || isMajorFixedFeastOfTheLord(day.date)) {
+  if (
+    day.weekday === 'sunday' ||
+    day.temporalCategory === 'privileged-feria' ||
+    day.temporalCategory === 'privileged-feria-major' ||
+    isMajorFixedFeastOfTheLord(day.date)
+  ) {
     return true;
   }
   return day.winner.kind === 'sanctoral' && isAtLeast(day.winner.rank, 'duplex-2-classis');