Add December Matins readings for SanctiM-track saints, completing the pass

13 of December's 15 SanctiM-track saints authored (st-bibiana, st-nicholas,
st-ambrose, immaculate-conception, st-damasus, st-lucy, st-thomas-apostle,
st-stephen-protomartyr, st-john-apostle, holy-innocents, st-thomas-becket,
st-silvester-i, st-eusebius-of-vercelli); st-barbara and st-melchiades left
unauthored as Common-only. This is the twelfth and final month of the
SanctiM (Monastic 1617)-track saints' Matins readings pass — 129 saints
authored across the whole year.

Adding St. Eusebius of Vercelli's content surfaces a 3rd Matins lesson on
the existing Advent III Tuesday proof date (Dec 15 falls under his
commemoration); updated matins.test.ts accordingly — the "commemorations
get their own reading" design working as intended, not a regression.

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

src/data/propers/nocturn-readings/st-eusebius-of-vercelli.yml

@@ -0,0 +1,121 @@
+# Matins Nocturn 2 reading for St. Eusebius of Vercelli, Bishop,
+# Martyr — vu places him Dec 15 (Monastic 1617's own same-day
+# redirect; see comment header in
+# src/data/calendar/saints/st-eusebius-of-vercelli.yml), but his real
+# proper content lives at the general Tridentine calendar's Dec 16
+# (`Sancti/12-16.txt`, confirmed via grep for "Eusebii Vercellensis"
+# across all Sancti files). No SanctiM file exists for him at either
+# date — a missed pre-1955-pool candidate, sourced the same way as a
+# pre-1955 saint (see memory vu-matins-pre1955-saints,
+# vu-matins-sanctim-saints).
+# web/www/horas/Latin/Sancti/12-16.txt, English/Sancti/12-16.txt.
+#
+# Nocturn 2: Lectio4-6 combined into one reading, one continuous vita.
+# Nocturn 3 (Lectio7-9) is a bare `@Commune/C2:LectioN in 2 loco`
+# rubric with no proper Lectio content in either language, so no
+# Nocturn 3 reading is authored here — correctly left unauthored, not
+# a gap.
+id: st-eusebius-of-vercelli
+readings:
+  - nocturn: 2
+    isGospel: false
+    text:
+      la: >-
+        Eusebius, natióne Sardus, Romanæ urbis lector, post Vercellénsis epíscopus, ad hanc
+        regéndam ecclésiam mérito est créditus divino eléctus judício: nam quem numquam ante
+        constitúti electóres cognoverant, posthábitis civibus, simul ut vidérunt, et
+        probavérunt; tantumque intérfuit, ut probarétur, quantum ut viderétur. Primus in
+        Occidéntis partibus in eadem ecclésia eosdem monachos instituit esse quos clericos, ut
+        esset in ipsis viris et contemptus rerum, et accurátio levitárum. Ariánis
+        impietátibus ea tempestáte per Occidéntem longe lateque traductis, advérsus eas
+        viríliter sic dimicávit, ut ejus invicta fides Libérium summum Pontificem ad vitæ
+        solátium erigeret. Quare hic sciens in ipso fervére Spíritum Dei, cum ei significasset
+        ut penes imperatórem una cum suis legátis patrocinium fidei susciperet, mox cum illis
+        profectus est ad Constántium; apud quem enixius agens, quidquid legatióne petebátur,
+        obtinuit, ut episcopórum nempe cœtus celebrarétur.
+
+
+        Colléctum est Mediolani anno sequénti concílium, ad quod a Constantio invitátum
+        Eusebium concupitúmque, ac vocátum a Liberii legatis, tantum abest, ut malignántium
+        synagóga Arianórum contra sanctum Athanasium furéntium in suas partes adduceret, ut
+        potius diserte statim ipse declarans, e præséntibus quosdam sibi compertos hæretica
+        labe pollutos, Nicænam immo fidem proposúerit iis subscribéndam, ántequam cetera
+        tractaréntur. Quod Ariánis acerbe irátis negántibus, nedum in Athanasium recusávit
+        ipse subscribere, quin sancti Dionýsii Mártyris, qui decéptus ab ipsis subscripserat,
+        captivatam simplicitátem ingeniosíssime liberávit. Quam ob rem illi gráviter
+        indignántes, post multas illatas injurias, exsílio illum mulctarunt: sed sanctus vir,
+        excusso púlvere, nec cæsaris minas veritus, nec enses obstrictos, exsílium véluti sui
+        ministerii offícium accépit; missusque Scythópolim, famem, sitim, verbera, divérsaque
+        supplícia perpéssus, pro fide strenue vitam contempsit, mortem non metuit, corpus
+        carnificibus trádidit.
+
+
+        Quanta in eum tunc Arianórum crudelitas fúerit ac effrons inverecúndia, ostendunt
+        graves litteræ plenæ róboris, pietátis ac religiónis, quas e Scythópoli scripsit ad
+        Vercellensem clerum et pópulum, aliosque finítimos; e quibus étiam est explorátum,
+        ipsórum nec minis, inhumanáque sævítia potuísse umquam eum deterreri, nec serpentina
+        blanda subtilitate ad eórum societátem perduci. Hinc in Cappadociam, postremoque ad
+        superiores Ægypti Thebáidas pro constántia sua deportatus, exsilii rigores tulit ad
+        mortem usque Constantii: post quam ad gregem suum reverti permissus, non prius redire
+        vóluit, quam reparandis fidei jacturis ad Alexandrinam synodum sese conferret, postque
+        médici præstántis instar, péragrans Oriéntis provincias, in fide infirmos ad
+        integram valetúdinem restitúeret, eos instítuens in Ecclésiæ doctrina. Inde
+        salubritate pari digresso in Illyricum, tandemque in Italiam delato, ad ejus réditum
+        lúgubres vestes Italia mutávit: ubi postquam Psalmórum ómnium expurgatos a se
+        commentarios Orígenis édidit, Eusebiíque Cæsareénsis, quos verterat de Græco in
+        Latinum; demum tot egregie factis illustris ad immarcescíbilem glóriæ corónam tantis
+        ærumnis proméritam, sub Valentiniáno et Valénte Vercellis migrávit.
+      en: >-
+        Eusebius was a Sardinian by birth, first a Reader in the Roman Church, and then Bishop
+        of Vercelli. It seemed specially designed by Providence that he should be called to
+        govern that Church, for the electors, who had never before known him, passed over,
+        with a strange unanimity, all their own fellow-citizens, and chose Eusebius, as soon as
+        they had seen him. He was the first Bishop in the Western Church who established an
+        Order of Regular Clergy, to combine the active with the contemplative life. At this
+        time the storm of Arian blasphemy and sin was sweeping far and wide over the West, and
+        Eusebius set himself to fight against it so manfully, that his unshaken faith brought
+        back Liberius again to life and hope. This Pope, knowing that the Spirit of God was in
+        him, sent him with his Legates to the Emperor Constantius, to plead the cause of the
+        Catholic Faith. His earnestness prevailed with that Prince, so that he obtained all
+        that was asked for, and, among other things, permission for a Council to be summoned.
+
+
+        The year following, the Council met at Milan, and Eusebius, by the invitation of the
+        Emperor, and the desire and command of the Papal Legates, attended. Here the Arians,
+        assembled in a perfect synagogue of Satan, and all furiously raging together against
+        holy Athanasius, found Eusebius one of the stoutest enemies of their faction. As soon
+        as he entered the Council, he delivered a long harangue, wherein he remarked that, of
+        those there gathered together, some were notoriously defiled with heresy, and
+        therefore he proposed that everyone should first of all subscribe the Nicene Creed,
+        before proceeding to any other business. The Arians, in a violent passion, refused,
+        whereupon he on his part refused to subscribe any proceedings against Athanasius, and
+        even skilfully procured the withdrawal of the signature of the holy martyr Denys, then
+        Bishop of Milan, which they had lyingly procured by practising on his simplicity. The
+        Arians were now entirely enraged, and, after many persecutions, procured a decree of
+        banishment against Eusebius. The Saint shook off the dust of his feet against them,
+        and, defying alike the threats of Caesar and the drawn swords of the soldiery, accepted
+        the sentence as one of the dignities of his office. He was sent to Bethshan in the Holy
+        Land, suffering hunger, thirst, stripes, and all manner of violence, but for the
+        Faith's sake he despised this life, and feared not death, but freely delivered his body
+        to the tormentors.
+
+
+        He wrote a solemn letter from Bethshan, addressed to the clergy and people of Vercelli
+        and that neighbourhood, full of constancy, devotion, and piety, describing the
+        frightful cruelty and brazen impudence of the Arians. From this letter we know how
+        completely they failed to scare him by their threats and their inhuman brutality, or to
+        seduce him by their serpent-like cunning into receiving their communion. In consequence
+        of his unshaken resolution, he was moved from Bethshan into Cappadocia, and then again,
+        to the deserts of Upper Egypt. He suffered exile until the death of Constantius, after
+        which he was allowed to return to his flock. First, however, he took care to attend the
+        Council at Alexandria, called to heal the wounds of the Church, and, afterwards, like a
+        skilful physician, he made a progress through all the provinces of the East,
+        strengthening those that were weak in the Faith, and confirming them in Christian
+        doctrine. Then, with the same healthful results, he passed through Illyricum into
+        Italy, who, at his coming, laid aside her garments of mourning. After his return, he
+        published an expurgated edition of Origen's Commentary on the Psalms, and likewise of
+        the works of Eusebius of Caesarea, both which he translated from Greek into Latin. At
+        length, distinguished by all these great works, he passed to that crown of glory which
+        fadeth not away, promised to them who suffer for the truth. He departed this present
+        life at Vercelli, in the reign of Valentinian and Valens.
+    status: { la: verified, en: verified }