Implement octave-vs-octave precedence, and fix a real day-label bug it surfaced

When more than one octave is active on a day with no temporal standing of
its own (St. Lawrence's and the Assumption's genuinely overlap every Aug
16-17), which one governs the day's content/label is now decided by rank
comparison instead of "whichever started first" (an accident of
insertion order). Per direct instruction:

- Highest effective rank wins outright; every other active octave still
  gets commemorated, same as a single octave already outranking a weak
  rival saint.
- A rank tie goes to whichever octave started more recently -- day 1 of
  a new octave needs to be fully present, the whole point of it
  starting. No real tied-rank case exists yet to verify this
  empirically, unlike everything else here -- documented in TODO.md as
  a stated decision, not a live finding.

New OctaveConfig.closingDayRank (default duplex): an octave's own final
day ("in Octava") is elevated above its ordinary in-between rank --
live-verified as a real, general pattern (both St. Lawrence's Aug 17 and
the Assumption's Aug 22 show as Duplex, above their otherwise-Semiduplex
ordinary days), not a one-off. This elevation is *why* Lawrence's octave
beats the Assumption's on their one real overlap day despite the
Assumption being the far higher-ranked feast overall. Feeds both the
existing rival-saint threshold and the new octave-vs-octave comparison.

calendar/octaves.ts gains resolveActiveOctave (+ pickWinningOctave, the
comparison itself factored out for direct unit testing against synthetic
data, since no real tied-rank overlap exists to test against yet).
hours/resolve-common.ts's resolveOfficeWinner and calendar/day-label.ts
both now call it instead of each keeping their own "activeOctavesFor(...)
[0]" logic.

That consolidation surfaced a real, independent bug: getDayLabel never
checked temporalCategory at all before choosing an octave name, unlike
resolveOfficeWinner -- found while testing the real Aug 16 overlap (a
Sunday that year, where the temporal Sunday has standing and should win
outright). Live-verified counterexample: the Christmas Octave's own
stack (Dec 30) was wrongly labeled "3rd Day within the Octave of The Holy
Innocents" instead of the correct plain temporal label -- the real title
never names any of the four stacked octaves there. Fixed by sharing the
exact same ordinary-feria gate resolveOfficeWinner already had, so the
two can no longer disagree.

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

tests/calendar/day-label.test.ts

@@ -62,6 +62,26 @@ describe('getDayLabel — active octave', () => {
   it("a season's own named anchor day outranks an active octave, even though Trinity Sunday is technically also day 8 of Pentecost's own octave", () => {
     expect(getDayLabel(resolveDay('2026-05-31'))).toBe('Trinity Sunday');
   });
+
+  it("a temporal day with real standing of its own (not ordinary-feria) never shows an octave name at all, even with one active -- live-verified counterexample: the Christmas Octave's own stack (Dec 30) titles itself off the Sunday, never any of the four octaves layered on top of it", () => {
+    const day = resolveDay('2033-12-30');
+    expect(day.temporalCategory).toBe('privileged-feria-minor');
+    expect(getDayLabel(day)).not.toContain('Octave');
+    expect(getDayLabel(day)).toBe('Friday in Christmastide');
+  });
+
+  it("picks the higher-ranked of two genuinely overlapping octaves for the label -- St. Lawrence's own elevated closing day (Aug 17) over the Assumption's ordinary day 3, even though the Assumption's octave started later and the Assumption is the higher-ranked feast overall", () => {
+    expect(getDayLabel(resolveDay('2026-08-17'))).toBe('8th Day within the Octave of St. Lawrence, Martyr');
+    expect(getDayLabel(resolveDay('2026-08-18'))).toBe('4th Day within the Octave of The Assumption of the Blessed Virgin Mary');
+  });
+
+  it('a real Sunday with standing of its own wins over both octaves entirely, showing the plain ordinal Sunday label -- not an octave name at all', () => {
+    // 2026-08-16 is a Sunday genuinely within both St. Lawrence's and the
+    // Assumption's overlapping octave windows.
+    const day = resolveDay('2026-08-16');
+    expect(day.weekday).toBe('sunday');
+    expect(getDayLabel(day)).not.toContain('Octave');
+  });
 });
 
 describe('getDayLabel — feast name combination', () => {