Strengthen the Immaculate Conception's and Nativity BVM's octaves too

Same `wins: duplex` override as the Assumption's and Pentecost's
octaves, applied to two more common-class octaves. Accepted side
effect: St. Damasus (Dec 11) and St. Nicholas of Tolentino (Sep 10),
both Semiduplex, no longer tie-and-win an ordinary octave day here --
they're now commemorated instead of winning outright.

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

src/data/calendar/saints/immaculate-conception.yml

@@ -9,5 +9,11 @@ common: common-of-the-bvm
 propers: "immaculate-conception"
 minorHoursCommon: common-of-the-bvm
 # Has a real octave (Dec 8-15) -- see calendar/types.ts's OctaveConfig.
+# Strengthened to `wins: duplex` (2026-08 user decision), same pattern
+# as pentecost-sunday.yml's and assumption.yml's own overrides. Side
+# effect accepted by the user: St. Damasus (Dec 11, semiduplex) no
+# longer ties and wins an ordinary octave day here -- he now loses
+# outright to the octave instead (see st-damasus.yml).
 octave:
   enabled: true
+  wins: duplex

src/data/calendar/saints/nativity-bvm.yml

@@ -10,5 +10,12 @@ common: common-of-the-bvm
 propers: "nativity-bvm"
 minorHoursCommon: common-of-the-bvm
 # Has a real octave (Sep 8-15) -- see calendar/types.ts's OctaveConfig.
+# Strengthened to `wins: duplex` (2026-08 user decision), same pattern
+# as pentecost-sunday.yml's and assumption.yml's own overrides. Side
+# effect accepted by the user: St. Nicholas of Tolentino (Sep 10,
+# semiduplex) no longer ties and wins an ordinary octave day here -- he
+# now loses outright to the octave instead (see
+# st-nicholas-of-tolentino.yml).
 octave:
   enabled: true
+  wins: duplex