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/january-sanctoral.test.ts

@@ -48,10 +48,21 @@ describe('January sanctoral pull (first pass)', () => {
   it('a simplex saint on an ordinary Sunday is commemorated, not dropped or made to win', () => {
     // Jan 14, 2029 is the Second Sunday after Epiphany (ordinary, not
     // privileged) — St. Felix (simplex) is commemorated per the ordinary-
-    // Sunday rule, matching the historical calendar exactly.
+    // Sunday rule, matching the historical calendar exactly. St. Hilary of
+    // Poitiers (Semiduplex, also native to this date) is commemorated too
+    // -- live-verified (Divino Afflatu 1954) as the real, sole
+    // commemoration named there; this app's own generous-commemoration
+    // design (see CLAUDE.md) additionally keeps St. Felix rather than
+    // dropping him now that Hilary no longer needs the day to himself.
     const day = resolveDay('2029-01-14');
     expect(day.winner).toEqual({ kind: 'temporal', id: 'post-epiphany-2' });
     expect(day.commemorations).toEqual([
+      {
+        kind: 'sanctoral',
+        id: 'st-hilary-of-poitiers',
+        name: 'St. Hilary of Poitiers, Bishop, Confessor and Doctor of the Church',
+        rank: 'semiduplex',
+      },
       { kind: 'sanctoral', id: 'st-felix-presbyter', name: 'St. Felix, Priest and Martyr', rank: 'simplex' },
     ]);
   });