fix(cli): render the Second reading on colitur readings

The OF lectionary (data/of/lectionary.sexp) carries 183 Second readings,
146 of them on Sunday keys, and the kernel resolves them correctly -- but
readings_line (EF) and readings_line_of (OF) in bin/main.ml only ever
printed Citation.First and Citation.Gospel, so `colitur readings --rite of`
silently dropped every Second reading it computed.

Both functions gain a second_suffix lookup, spliced between the existing
First and Gospel fields, present only when the day carries a Second
citation. No rite check: EF's citation_shapes is [[First; Gospel]] alone,
so EF rows are unaffected by construction, not by special-casing.

EF byte-identity verified two ways: `git diff --stat v1.0.0..HEAD --
data/ef/` is empty, and `colitur day`/`colitur readings --rite ef` for
2026, 1583 and 9999 cmp identical against a build of the prior commit.

test/cli.t: fixed the one now-stale assertion and added coverage for the
three-citation OF Sunday shape alongside the unchanged two-citation OF
weekday and EF shapes.

2 files changed, 54 insertions, 3 deletions

diff --git a/bin/main.ml b/bin/main.ml
index eab41d8..6e3b03c 100644
--- a/bin/main.ml
+++ b/bin/main.ml
@@ -473,13 +473,32 @@ let readings_line ~lang ~sigla (d : (Rite_ef.Vocab_ef.season, Rite_ef.Vocab_ef.r
     | Some c -> Colitur_citation.Sigla.format sigla c.Colitur_kernel.Citation.reference
     | None -> "-"
   in
+  (* The Second reading (OLM n. 67: a Sunday/solemnity's own three-reading
+     shape) is present-or-absent, not present-or-"-": unlike First/Gospel
+     ({!Colitur_kernel.Validate}'s "citations" check guarantees exactly one
+     of each on every day of every rite), a day may legitimately carry no
+     Second reading at all ([Rite.t.citation_shapes] for EF is
+     [[First; Gospel]] alone), and EF never carries one. So this is an
+     append-only field, the same discipline [name_suffix] below already
+     uses -- absent, it contributes the empty string and this row is
+     byte-identical to what it printed before the Second reading existed. *)
+  let second_suffix =
+    match
+      List.find_opt
+        (fun (c : Colitur_kernel.Citation.t) -> c.Colitur_kernel.Citation.part = Colitur_kernel.Citation.Second)
+        d.Colitur_kernel.Liturgical_day.citations
+    with
+    | Some c -> " | " ^ Colitur_citation.Sigla.format sigla c.Colitur_kernel.Citation.reference
+    | None -> ""
+  in
   let slug_s = Colitur_kernel.Slug.to_string cel.Colitur_kernel.Celebration.slug in
   let name = Colitur_naming.Lang.celebration lang slug_s in
   let name_suffix = if name = slug_s then "" else " | " ^ name in
-  Printf.printf "%s %s | %s | %s%s\n"
+  Printf.printf "%s %s | %s%s | %s%s\n"
     (D.to_iso8601 d.Colitur_kernel.Liturgical_day.date)
     slug_s
     (part_ref Colitur_kernel.Citation.First)
+    second_suffix
     (part_ref Colitur_kernel.Citation.Gospel)
     name_suffix
 
@@ -736,13 +755,27 @@ let readings_line_of ~lang ~sigla
     | Some c -> Colitur_citation.Sigla.format sigla c.Colitur_kernel.Citation.reference
     | None -> "-"
   in
+  (* Second reading: present-or-absent, not present-or-"-" -- see
+     [readings_line]'s own comment for the full reasoning (OLM n. 67, a
+     Sunday/solemnity's own three-reading shape; [Rite.t.citation_shapes]
+     is what actually distinguishes which OF days carry one). *)
+  let second_suffix =
+    match
+      List.find_opt
+        (fun (c : Colitur_kernel.Citation.t) -> c.Colitur_kernel.Citation.part = Colitur_kernel.Citation.Second)
+        d.Colitur_kernel.Liturgical_day.citations
+    with
+    | Some c -> " | " ^ Colitur_citation.Sigla.format sigla c.Colitur_kernel.Citation.reference
+    | None -> ""
+  in
   let slug_s = Colitur_kernel.Slug.to_string cel.Colitur_kernel.Celebration.slug in
   let name = observed_name_of ~lang cel slug_s in
   let name_suffix = if name = slug_s then "" else " | " ^ name in
-  Printf.printf "%s %s | %s | %s%s\n"
+  Printf.printf "%s %s | %s%s | %s%s\n"
     (D.to_iso8601 d.Colitur_kernel.Liturgical_day.date)
     slug_s
     (part_ref Colitur_kernel.Citation.First)
+    second_suffix
     (part_ref Colitur_kernel.Citation.Gospel)
     name_suffix
 
diff --git a/test/cli.t b/test/cli.t
index 86291a6..588616c 100644
--- a/test/cli.t
+++ b/test/cli.t
@@ -230,7 +230,25 @@ The OF rite resolves too, same two commands, its own vocabulary:
   $ colitur readings --rite of 2026 | wc -l
   365
   $ colitur readings --rite of 2026 | head -1
-  2026-01-01 of-mary-mother-of-god | Num 6:22-27 | Luc 2:16-21
+  2026-01-01 of-mary-mother-of-god | Num 6:22-27 | Gal 4:4-7 | Luc 2:16-21
+
+fix-render-second-report (2026-08-26): the Second reading (OLM n. 67) now
+renders between First and Gospel on the days that carry one -- a Sunday or
+solemnity, [Rite.t.citation_shapes] on the OF side -- and is simply absent
+(not printed as "-") on every other day, so an OF weekday's row keeps the
+same two-citation shape it always had:
+
+  $ colitur readings --rite of 2026 | grep '^2026-11-29 '
+  2026-11-29 of-advent-sunday-1 | Isai 63:16b-17, 19b; 64:2-7 | 1 Cor 1:3-9 | Marc 13:33-37
+  $ colitur readings --rite of 2026 | grep '^2026-01-05 '
+  2026-01-05 of-christmas-1-monday | 1 Ioann 3:11-21 | Ioann 1:43-51
+
+EF's own `citation_shapes` is `[First; Gospel]` alone -- no EF day ever
+carries a Second reading, so EF's `readings` row is unaffected, still
+exactly two citation fields:
+
+  $ colitur readings --rite ef 2026 | grep '^2026-01-01 '
+  2026-01-01 ef-circumcision | Tit 2:11-15 | Luc 2:21 | In Octava Nativitatis Domini
 
 Fix wave I1 (final-review.md): a sanctoral-origin OF day names through its
 OWN transcribed title (calendar-2002.sexp, amended by 011's own rename),