Fix ordinary-Sunday precedence and unify getDayLabel's commemoration rendering

Two related fixes surfaced while chasing why St. Gregory Thaumaturgus
appeared to be misdated on Nov 18:

- calendar/commemorations.ts's `ordinary-sunday` case was transferring a
  Semiduplex (or lower) saint off the Sunday instead of commemorating it
  in place — an earlier, unverified guess. Live-verified against both
  Tridentine 1906 and Divino Afflatu 1954 (St. Gregory Thaumaturgus, St.
  Clement, St. Apollinaris, St. Thomas Becket, all real cases): the saint
  stays and is commemorated on the Sunday itself, same as Simplex, never
  pushed to the next open day. This is what was actually moving Gregory
  onto Nov 18 — not a data error. `applyChristmasOctaveSunday`'s own
  Dec 26-29 special case needed a matching adjustment (per its own
  documented intent, the displaced saint there is deliberately *not*
  commemorated in place, since he reappears in full on Dec 30 instead).

- getDayLabel had five branches, each hand-assembling its own
  filter/format logic for which commemorations to show — which is why
  the octave phrasing, the closing-day title, and a missing Sunday
  commemoration turned into three separate bugs earlier instead of one.
  Replaced with a single shared `collectCommemorations` used by every
  branch. This also exposed that the sanctoral-winner branch never
  showed any commemorated saint at all, and every other branch only
  showed the *first* one (`.find()`), silently dropping real collisions
  — both now show every commemorated saint, matching this app's own
  generous-commemoration design.

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

tests/calendar/christ-the-king.test.ts

@@ -11,7 +11,12 @@ describe('Christ the King (applyChristTheKing)', () => {
     const day = resolveDay('2026-10-25'); // last Sunday of October 2026
     expect(day.winner).toEqual({ kind: 'temporal', id: 'christ-the-king' });
     expect(day.commemorations).toContainEqual({ kind: 'temporal', id: 'post-pentecost-22' });
-    expect(getDayLabel(day)).toBe('Christ the King (Duplex I Class)');
+    // Live-verified (Divino Afflatu 1954): the day's own commemoration
+    // line also names whichever sanctoral entry the ordinary Sunday was
+    // already carrying (Ss. Chrysanthus and Daria, Simplex, per the next
+    // test below) -- this app's day label now surfaces every commemorated
+    // saint, not just the Sunday itself.
+    expect(getDayLabel(day)).toBe('Christ the King (Duplex I Class) — Ss. Chrysanthus and Daria, Martyrs');
   });
 
   it('preserves a nested commemoration: a Simplex saint already commemorated under the ordinary Sunday stays commemorated', () => {