Add per-Common-category Matins responsory pool, expand per-book pool

The per-book responsory pool (Nocturn 1 scripture readings) only had `isa`
seeded; the much bigger, previously untracked gap was that 272 of 355
nocturn-readings/*.yml files (Nocturn 2/3 patristic readings) had no
responsory at all. Added a sibling per-Common-category pool, sourced from
the reference engine's static Commune text files, covering all 19 of vu's
real `common:` category ids (several confirmed aliases of the same
underlying file). Wired into matins.ts's reading assembly as a fallback
when a reading has no proper responsory of its own. Also expanded the
per-book pool with `gen` and `jer`.

Live-verified end-to-end (St. Francis de Sales, Ss. Cornelius/Cyprian, Ss.
Euphemia/Lucy/Geminianus). npm test (2025 passed) and tsc --noEmit pass.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AGjUyhUZJaSjiniEmnLdak

src/propers/matins-responsories.ts

@@ -2,6 +2,11 @@
 // data/hours/matins-responsories-by-book.yml's own header for why matching
 // is book-level, not citation-level, and why this is a seeded subset, not
 // a full pool.
+//
+// This file also holds the sibling per-Common-category pool (see
+// data/hours/matins-responsories-by-common.yml's own header) — used to
+// fill in a real responsory for a saint's own Nocturn 2/3 patristic
+// reading when that reading has no proper `responsory` of its own.
 import type { LanguageCode, TranslationStatus } from '../psalter/types';
 
 interface BilingualText {
@@ -56,3 +61,38 @@ export function getResponsoryForBook(book: string, index: number): MatinsRespons
   if (!pool || pool.length === 0) return undefined;
   return joinResponsory(pool[index % pool.length]!);
 }
+
+interface FullTextResponsory {
+  la: string;
+  en: string;
+}
+
+const commonModules = import.meta.glob<{ default: Record<string, FullTextResponsory[]> }>(
+  '../data/hours/matins-responsories-by-common.yml',
+  { eager: true },
+);
+
+const poolByCommon = new Map<string, FullTextResponsory[]>();
+for (const mod of Object.values(commonModules)) {
+  for (const [commonId, entries] of Object.entries(mod.default)) {
+    poolByCommon.set(commonId, entries);
+  }
+}
+
+/** Same cycling convention as getResponsoryForBook, but the pooled text is
+ * already the full "R. ...\n* ...\nV. ...\nR. ..." block (matching the
+ * inline `responsory` convention every nocturn-readings/*.yml file uses),
+ * ready to drop straight into a reading's `responsory` field — not the
+ * split {r, v} shape the book pool uses. Undefined when the saint has no
+ * `common` category, or that category isn't seeded (e.g. angel/evangelist/
+ * vigil — see the data file's own header for why those are out of scope). */
+export function getResponsoryForCommon(
+  commonId: string | undefined,
+  index: number,
+): Partial<Record<LanguageCode, string>> | undefined {
+  if (!commonId) return undefined;
+  const pool = poolByCommon.get(commonId);
+  if (!pool || pool.length === 0) return undefined;
+  const entry = pool[index % pool.length]!;
+  return { la: entry.la, en: entry.en };
+}