Strengthen the Assumption's octave against a demoted St. John Eudes

Demote St. John Eudes (Aug 19) from Duplex to Semiduplex -- too minor
a confessor to keep outranking the Assumption's octave. To make that
demotion actually cede the day, raise the Assumption's octave to
`wins: duplex` (same pattern already used by Pentecost's octave), so an
ordinary-day tie no longer automatically favors the occurring saint.

Promote St. Thomas of Canterbury (Dec 29) to Duplex so he keeps
winning against the Christmas octave stack now that ordinary-day ties
are no longer a given.

Also add a closing-day tie-break to octave-vs-octave precedence
(pickWinningOctave): when two active octaves tie in rank, the one on
its own closing day now wins the label contest, ahead of the existing
"more recently started" tie-break. Needed because Assumption's day 3
and St. Lawrence's own closing day (Aug 17) now tie at Duplex, and the
closing day should still govern that date's label.

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

tests/calendar/december-sanctoral.test.ts

@@ -88,13 +88,13 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
     ]);
   });
 
-  it('St. Thomas of Canterbury, only Semiduplex, still wins outright within the Christmas Octave -- the concrete case behind this month\'s temporal-category fix', () => {
+  it('St. Thomas of Canterbury still wins outright within the Christmas Octave -- the concrete case behind this month\'s temporal-category fix', () => {
     const day = resolveDay('2033-12-29');
     expect(day.winner).toEqual({
       kind: 'sanctoral',
       id: 'st-thomas-becket',
       name: 'St. Thomas of Canterbury, Bishop and Martyr',
-      rank: 'semiduplex',
+      rank: 'duplex',
     });
     // Thomas himself has no octave (user-confirmed, 2026-08), but by his
     // own day, Christmas + Stephen + John + Holy Innocents' octaves have
@@ -128,7 +128,7 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
   });
 
   it('the Christmas Octave Sunday still keeps a lesser feast from winning, now via applyChristmasOctaveSunday specifically', () => {
-    // St. Thomas Becket (Semiduplex, Dec 29) transfers off the Sunday
+    // St. Thomas Becket (Dec 29) transfers off the Sunday
     // rather than winning it -- per calendar/index.ts's
     // applyChristmasOctaveSunday (see its own dedicated test file), which
     // now unconditionally wins the Sunday over *any* rank within Dec
@@ -144,7 +144,7 @@ describe('December sanctoral pull (first pass, 12/12)', () => {
       kind: 'sanctoral',
       id: 'st-thomas-becket',
       name: 'St. Thomas of Canterbury, Bishop and Martyr',
-      rank: 'semiduplex',
+      rank: 'duplex',
     });
   });