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/christmas-octave-sunday.test.ts

@@ -66,7 +66,7 @@ describe('applyChristmasOctaveSunday', () => {
     expect(dec30.commemorations.some((c) => c.kind === 'octave' && c.id === 'holy-innocents')).toBe(false);
   });
 
-  it('Sunday on Dec 29 (St. Thomas Becket, only Semiduplex): still fully displaced to Dec 30, same as the Duplex-II-classis saints -- rank never matters for this rule', () => {
+  it('Sunday on Dec 29 (St. Thomas Becket): still fully displaced to Dec 30, same as the Duplex-II-classis saints -- rank never matters for this rule', () => {
     const sunday = resolveDay('2024-12-29');
     expect(sunday.winner).toEqual({ kind: 'temporal', id: 'christmas-octave-sunday' });
 
@@ -75,7 +75,7 @@ describe('applyChristmasOctaveSunday', () => {
       kind: 'sanctoral',
       id: 'st-thomas-becket',
       name: 'St. Thomas of Canterbury, Bishop and Martyr',
-      rank: 'semiduplex',
+      rank: 'duplex',
     });
   });
 
@@ -105,7 +105,7 @@ describe('applyChristmasOctaveSunday', () => {
       kind: 'sanctoral',
       id: 'st-thomas-becket',
       name: 'St. Thomas of Canterbury, Bishop and Martyr',
-      rank: 'semiduplex',
+      rank: 'duplex',
     });
   });