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
