Merge branch 'robustness-and-hackability'

An audit of the shipped program, plus the fixes it found.

The citation parser accepted OCaml integer-literal syntax, so a typo like
'Luke 1_1:5' silently became a different chapter. Four pairs of different
books shared a full title -- 1 and 2 Corinthians both rendered 'Epistola
ad Corinthios' -- leaving 108 citations in 2027 alone that a reader could
not resolve to a book. Spec section 8.5 is now delivered rather than
recorded: shipped styles re-parse their own output. Overlay errors no
longer name OCaml source files at the reader.

Also: the new-overlay scaffold shows citations at the right nesting
level, config --show validates before printing, error messages no longer
echo whole file lines, and a month answers to both spellings of its own
name.

1 files changed, 30 insertions, 4 deletions

diff --git a/man/colitur-templates.5 b/man/colitur-templates.5
index e04560b..e668b55 100644
--- a/man/colitur-templates.5
+++ b/man/colitur-templates.5
@@ -566,13 +566,21 @@ template iterates over directly, without going through
 .BR months .
 .SS month
 .TP
-.B num
-The month number, 1 through 12, as a string.
+.BR num ", " month_num
+The month number, 1 through 12, as a string. The two spellings are the same
+value \(em see the note at the end of this subsection.
 .TP
-.B name
+.BR name ", " month_name
 The month's own resolved display name in the active language (e.g.
 .RB \(lq Ianuarius \(rq ),
-a plain string.
+a plain string. Both spellings are the same value.
+.TP
+.B month_abbr
+The month's abbreviated name in the active language (e.g.
+.RB \(lq Ian \(rq ),
+from the language file's own
+.B [month_abbr]
+section.
 .TP
 .B days
 This month's own
@@ -587,6 +595,24 @@ last rows padded with blank cells (see
 .B day \(->  in_month
 below) so every row has seven entries regardless of which weekday the month
 starts or ends on.
+.PP
+.B "Why two spellings."
+A
+.B week
+object (below) carries
+.BR month_name ", " month_num " and " month_abbr,
+because at that level a bare
+.B name
+would be ambiguous. An author who learned those names inside
+.B {{#weeks}}
+naturally reaches for them one level up, inside
+.BR {{#months}} .
+Before colitur 0.9 they resolved to nothing there, and because an unknown
+key renders as the EMPTY STRING by design (see
+.B SCOPE AND LOOKUP
+above), the result was a silently blank month heading rather than any
+error. A month now answers to both. Prefer the short forms in new
+templates: a month is the only scope where they are unambiguous.
 .SS week
 .TP
 .B num