calendar: pull April's sanctoral calendar (pre-1955 pull, 4/12)

12 saints for April (11 real + St. Catherine of Siena as a stub), all
winning outright on a clean per-annum date.

Two real methodological findings this month:
- St. Mark (Apr 25, Duplex II. classis) directly confirms the
  privileged-feria-major behavior from the previous fix: he only ever
  gets commemorated within the Easter Octave, never wins there.
- St. Robert/St. Catherine of Siena (Apr 29) is a genuine, year-stable
  monastic-calendar reassignment — this app's own base Latin source data
  files that date's Roman-calendar content under a different saint (Peter
  Martyr) entirely, which a naive raw-file lookup by MM-DD would have
  missed; the live per-date query resolved it correctly regardless, and
  is what these records are actually built from. Worth remembering for
  future months.

New common category: common-of-an-evangelist (St. Mark, an Evangelist
but not an Apostle).

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

src/data/calendar/saints/ss-cletus-and-marcellinus.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-26, no Sunday collision) -- winner outright, Semiduplex.
+# No unique Oratio/Antiphon -- Common of Several Martyrs only.
+id: ss-cletus-and-marcellinus
+name: "Ss. Cletus and Marcellinus, Popes and Martyrs"
+rank: semiduplex
+common: common-of-several-martyrs
+propers: null

src/data/calendar/saints/ss-soter-and-caius.yml

@@ -0,0 +1,11 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-22, no Sunday collision) -- winner outright, Semiduplex.
+# The source shows an alternate [Officium] block tagged "(rubrica 196)"
+# -- a later rubric renumbering, not this app's target era, so the
+# untagged/default block is used, same convention as every other saint in
+# this set. No unique Oratio/Antiphon -- Common of Several Martyrs only.
+id: ss-soter-and-caius
+name: "Ss. Soter and Caius, Popes and Martyrs"
+rank: semiduplex
+common: common-of-several-martyrs
+propers: null

src/data/calendar/saints/ss-tiburtius-valerian-and-maximus.yml

@@ -0,0 +1,9 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2043-04-14, a year St. Francis of Paola doesn't transfer here) --
+# winner outright, Simplex. Own proper collect, no unique antiphon of
+# their own.
+id: ss-tiburtius-valerian-and-maximus
+name: "Ss. Tiburtius, Valerian, and Maximus, Martyrs"
+rank: simplex
+common: common-of-several-martyrs
+propers: "ss-tiburtius-valerian-and-maximus"

src/data/calendar/saints/st-anicetus.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-17, no Sunday collision) -- winner outright, Simplex. No
+# unique Oratio/Antiphon in the source -- Common of a Martyr Bishop only.
+id: st-anicetus
+name: "St. Anicetus, Pope and Martyr"
+rank: simplex
+common: common-of-a-martyr-bishop
+propers: null

src/data/calendar/saints/st-catherine-of-siena.yml

@@ -0,0 +1,13 @@
+# Secondary commemoration on 04-29 (loses the day to St. Robert, Abbot --
+# see st-robert.yml's note on this being a fixed monastic-calendar
+# reassignment, confirmed stable across two different years). Her real
+# historical/Roman-calendar date is Apr 30, but in this monastic calendar
+# specifically she sits on Apr 29 as Robert's secondary instead. No live
+# query exposes a secondary entry's own rank -- simplex here is an
+# unverified placeholder, same caveat as every other stub in this set.
+# No text pulled at all yet.
+id: st-catherine-of-siena
+name: "St. Catherine of Siena, Virgin"
+rank: simplex
+common: common-of-a-virgin
+propers: null

src/data/calendar/saints/st-francis-of-paola.yml

@@ -0,0 +1,11 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-14) -- his native date is Apr 2, but Holy Week blocked him
+# that year and he transferred here instead, winning outright against
+# Ss. Tiburtius/Valerian/Maximus (his own file's own real content, so still
+# reliably read even though the date isn't his usual one) -- Duplex. Own
+# proper collect, no unique antiphon of his own.
+id: st-francis-of-paola
+name: "St. Francis of Paola, Confessor"
+rank: duplex
+common: common-of-a-confessor
+propers: "st-francis-of-paola"

src/data/calendar/saints/st-george.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-23, no Sunday collision) -- winner outright, Semiduplex.
+# Own proper collect, no unique antiphon of his own.
+id: st-george
+name: "St. George, Martyr"
+rank: semiduplex
+common: common-of-a-martyr
+propers: "st-george"

src/data/calendar/saints/st-leo-i.yml

@@ -0,0 +1,12 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2043-04-11, clear of the Easter Octave that usually overshadows
+# this date, and not a Sunday) -- winner outright, Duplex. Own proper
+# collect (marked in the source as used "nisi communi Summorum
+# Pontificum" -- unless the Common of Popes formula applies instead; used
+# here regardless, matching how every other saint's own proper collect in
+# this set is preferred over a Common). No unique antiphon of his own.
+id: st-leo-i
+name: "St. Leo I, Pope, Confessor and Doctor of the Church"
+rank: duplex
+common: common-of-a-confessor-bishop
+propers: "st-leo-i"

src/data/calendar/saints/st-mark.yml

@@ -0,0 +1,13 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-25, no Sunday collision) -- winner outright, Duplex II.
+# classis. When this date falls within the Easter Octave instead (see
+# calendar/temporal-categories.yml's privileged-feria-major note), he's
+# merely commemorated, never wins -- the case that helped verify the
+# privileged-feria/privileged-feria-major split. Own proper collect, no
+# unique antiphon of his own. An Evangelist but not an Apostle, so a new
+# category: "common-of-an-evangelist".
+id: st-mark
+name: "St. Mark, Evangelist"
+rank: duplex-2-classis
+common: common-of-an-evangelist
+propers: "st-mark"

src/data/calendar/saints/st-peter-martyr.yml

@@ -0,0 +1,11 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-30) -- winner outright, Semiduplex. St. Peter of Verona,
+# not the Apostle. Own proper collect, no unique antiphon of his own. See
+# st-robert.yml's note: this app's base Latin source data files this
+# saint's content under 04-29.txt (his Roman-calendar date), even though
+# he lands on Apr 30 in this monastic calendar specifically.
+id: st-peter-martyr
+name: "St. Peter Martyr, Martyr"
+rank: semiduplex
+common: common-of-a-martyr
+propers: "st-peter-martyr"

src/data/calendar/saints/st-robert.yml

@@ -0,0 +1,17 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2029-04-29 and again 2043-04-29, confirming this is a fixed
+# monastic-calendar reassignment, not year-dependent like St. Francis of
+# Paola's transfer) -- winner outright, Duplex, over St. Catherine of
+# Siena (see st-catherine-of-siena.yml). Own proper collect, no unique
+# antiphon of his own. Genuine methodological note: this app's base Latin
+# source data files the Roman-calendar content for this date (04-29.txt)
+# under St. Peter Martyr instead -- Robert's own real content lives
+# somewhere the monastic-specific delta correctly resolves to, which the
+# live-engine query reaches even though a naive raw-file lookup by MM-DD
+# wouldn't have. Worth remembering if a future month's raw-file check
+# ever seems to contradict what a live query actually shows.
+id: st-robert
+name: "St. Robert, Abbot"
+rank: duplex
+common: common-of-an-abbot
+propers: "st-robert"

src/data/calendar/saints/st-vitalis.yml

@@ -0,0 +1,8 @@
+# Verified against Divinum Officium (Monastic Tridentinum 1617), live kalendar
+# check (2042-04-28, no Sunday collision) -- winner outright, Simplex. Own
+# proper collect, no unique antiphon of his own.
+id: st-vitalis
+name: "St. Vitalis, Martyr"
+rank: simplex
+common: common-of-a-martyr
+propers: "st-vitalis"

src/data/calendar/sanctoral-calendar.yml

@@ -67,6 +67,22 @@ days:
   "03-12": [st-gregory-the-great]
   "03-19": [st-joseph]
   "03-21": [st-benedict]
+  # April — 4/12 of the pre-1955 pull. St. Robert/St. Catherine of Siena
+  # (Apr 29) is a genuine monastic-calendar reassignment, not a mistake —
+  # see st-robert.yml. St. Francis of Paola's native date (Apr 2) often
+  # transfers due to Holy Week; that's the existing transfer machinery,
+  # not something recorded specially here.
+  "04-02": [st-francis-of-paola]
+  "04-11": [st-leo-i]
+  "04-14": [ss-tiburtius-valerian-and-maximus]
+  "04-17": [st-anicetus]
+  "04-22": [ss-soter-and-caius]
+  "04-23": [st-george]
+  "04-25": [st-mark]
+  "04-26": [ss-cletus-and-marcellinus]
+  "04-28": [st-vitalis]
+  "04-29": [st-robert, st-catherine-of-siena]
+  "04-30": [st-peter-martyr]
   "08-09": [vigil-of-st-lawrence]
   "08-10": [st-lawrence]
   "08-15": [assumption]