Add September Matins readings for SanctiM-track saints

All 9 of September's SanctiM-track saints authored -- the first full
month in this pass with nothing left unsourced. Includes the
Dedication of St. Michael the Archangel, whose SanctiM file borrows
structure from his separate May 8 Apparition file but still resolves
its actual readings back to this day's own Tridentine content.

src/data/propers/nocturn-readings/st-thecla.yml

@@ -0,0 +1,39 @@
+# Matins Nocturn 2 reading for St. Thecla, Virgin, Martyr (Sep 23,
+# sharing the date with St. Linus — see st-linus.yml). No genuine
+# SanctiM match: the only SanctiM file for this date bases
+# `@Sancti/09-23` (Linus, not Thecla) — a missed pre-1955-pool
+# candidate rather than a genuine SanctiM case (see memory
+# vu-matins-pre1955-saints, vu-matins-sanctim-saints).
+# web/www/horas/Latin/Sancti/09-23cc.txt, English/Sancti/09-23cc.txt.
+# Single lesson (simplex-feast Lectio93), one continuous account, no
+# responsory given in the source.
+id: st-thecla
+readings:
+  - nocturn: 2
+    isGospel: false
+    text:
+      la: >-
+        Thecla virgo, ex illustribus paréntibus Iconii nata, a Paulo Apóstolo fidei præceptis
+        instituta, miris sanctórum Patrum laudibus celebrátur. Quæ décimum octavum annum
+        agens, Thamíride sponso relícto, cum eam paréntes, quod Christiana esset,
+        accusassent, in ardentem rogum, qui, nisi Christo renuntiáret, ei parátus erat, prius
+        signo crucis armata, seipsam injecit. Sed igne, plúvia quæ repénte exorta est,
+        exstincto, Antiochíam venit; ubi, feris objecta et tauris in diversa incitátis
+        alligata, mox conjecta in fossam plenam serpéntibus, ex ómnibus Jesu Christi grátia
+        liberátur. Cujus ardore fidei et vitæ sanctitáte multi ad Christum convérsi sunt.
+        Iterum in pátriam rédiens, in montem sola secessit. Deínde, multis virtútibus et
+        miraculis insígnis, nonagenaria migrávit ad Dóminum, ac Seleucíæ sepúlta est.
+      en: >-
+        This virgin Thecla was the daughter of noble parents at Iconium, and a disciple of the
+        Apostle Paul. She is the subject of extraordinary praises by the holy Fathers. In the
+        eighteenth year of her age, she parted from one Thamiris, to whom she had been
+        betrothed, and her kindred accused her of being a Christian. A pile was set a-fire for
+        her, unless she should deny Christ, but she made the sign of the Cross, and willingly
+        entered it, and rain came, and put out the fire. She came to Antioch, where they threw
+        her to wild beasts; and strove to tear her asunder, by tying her to oxen driven
+        different ways; and cast her into a pit with many snakes; but by the mercy of Jesus
+        Christ she was delivered from all. The warmth of her faith and the holiness of her life
+        brought many to Christ. She returned into her own country, and withdrew to be an
+        hermit, alone on a certain mountain, and passed away to be with the Lord, aged ninety
+        years, and famous for many good works and miracles. She was buried at Seleucia.
+    status: { la: verified, en: verified }