feat(citation): the Sigla facade, total by construction

format never raises and returns an unparseable citation unchanged, so a
gap degrades to today's behaviour rather than to a crash. The coverage
test asserts separately that no shipped citation takes that path.

verbatim is what --raw uses: an identity name table would still reformat
punctuation and renumber, which would break byte-exact diffing against
lectio.

The existing citation-coverage walk (1970-2070) now also drives a
round-trip check in the same pass: parse -> render -> parse must reach
the same structure, using Book.default_spelling for names (Book.to_string
returns the internal id, which is not a registered token and cannot be
read back). Proved with a mutation: changing the default style's
part_sep to a separator the parser does not accept reddened the
round-trip case on 31 multi-part citations and nothing else; reverted.

1 files changed, 1 insertions, 0 deletions

diff --git a/test/test_colitur.ml b/test/test_colitur.ml
index 6084adb..c873945 100644
--- a/test/test_colitur.ml
+++ b/test/test_colitur.ml
@@ -8,6 +8,7 @@ let () =
       Test_citation.suite;
       ("parse", Test_citation.parse_suite);
       Test_citation.render_suite;
+      ("sigla", Test_citation.sigla_suite);
       Test_config.suite;
       Test_overlay.suite; Test_overlay_ini.suite; Test_temporal_ef.suite; Test_validate.suite; Test_precedence.suite;
       Test_calendar.suite; Test_precedence_ef.suite; Test_sanctoral_ef.suite; Test_rite_ef.suite;