feat(clectio-gen): apply a calendar layer/sanctorale when generating

Add opt-in flags so clectio's tables can be regenerated from a customized
calendar instead of only the embedded universal one:

  clectio-gen -caldir DIR -use a,b [-sanctorale DIR] <new|old> y0 y1 out/

- -caldir + -use stack calendar layers (rank, colour, name, reading.*) over the
  calendar; -sanctorale DIR applies a full of.ini/ef.ini replacement.
- The BOOK table stays hermetic (LECTIO_CONFIG still points nowhere), so the
  generator can't read a stale user books.ini -- calendar customization and the
  book aliases are kept separate concerns.
- config.SetCalendarsDir lets CalendarsDir be pointed at an explicit layer dir
  without a full config tree (and without an unrelated books.ini there).

Verified end to end: a layer adding a feast with a proper gospel regenerates
into liturgy_of.h + verses_of.keys, and the rebuilt clectio shows it. Default
(no flags) output is byte-identical to before. make test green.

0 files changed, 0 insertions, 0 deletions