bible(corpus-check): warn on a verse present but stubbed vs the Vulgate

The count-based checks (gap, duplicate, missing chapter) only see a verse's
presence, so a verse that IS there but truncated -- a lost opening line, a merge
artifact, the exact class that lost 44 psalm openings and Acts 6:5 from the old
Wujek scrape -- passes silently.

Add a warning for it, compared CROSS-CORPUS to the aligned Vulgate verse (never
within the chapter). That is deliberate: a genuinely terse verse ("Non occides",
"Jesus wept") is short in the Vulgate too, so it is not flagged; only a corpus
stub against a substantial Vulgate verse fires (corpus <12 chars, <1/4 of a
Vulgate verse >=40). Rune-counted (script-agnostic) and skipped on the Psalms
when the corpus renumbers them (psalm_system != vulgate), where per-verse
alignment with the Vulgate would not hold.

Warning only, never an error. Zero false positives across vul/wuj/drb/grb;
a `stub` testdata fixture (Genesis 1:1 = "x") exercises a real hit.

4 files changed, 59 insertions, 4 deletions

diff --git a/internal/bible/testdata/corpora/stub.ini b/internal/bible/testdata/corpora/stub.ini
new file mode 100644
index 0000000..3ba9b6e
--- /dev/null
+++ b/internal/bible/testdata/corpora/stub.ini
@@ -0,0 +1,4 @@
+; test fixture: a present-but-truncated verse (Genesis 1:1 is a stub vs vul)
+lang = en
+name = Stub Test Corpus
+psalm_system = vulgate
diff --git a/internal/bible/testdata/corpora/stub.tsv b/internal/bible/testdata/corpora/stub.tsv
new file mode 100644
index 0000000..3dd4551
--- /dev/null
+++ b/internal/bible/testdata/corpora/stub.tsv
@@ -0,0 +1,2 @@
+Genesis	Gn	1	1	1	x
+Genesis	Gn	1	1	2	And the earth was void and empty, and darkness covered the deep.
diff --git a/internal/bible/validate.go b/internal/bible/validate.go
index 27ec519..9c99436 100644
--- a/internal/bible/validate.go
+++ b/internal/bible/validate.go
@@ -3,6 +3,8 @@ package bible
 import (
 	"fmt"
 	"sort"
+	"strings"
+	"unicode/utf8"
 )
 
 // CorpusReport is the outcome of validating one corpus's sidecar + text (see
@@ -34,7 +36,10 @@ var validPsalmSystems = map[string]bool{"vulgate": true, "hebrew": true, "drb":
 // chapter, or a repeated verse number within a chapter, is a warning only --
 // real source texts legitimately do this (e.g. the LXX's lettered doublet
 // verses in 3 Kingdoms, or a scanned translation's occasional merged verse),
-// and it must never turn a corpus that otherwise loads fine into a failure.
+// and it must never turn a corpus that otherwise loads fine into a failure. A
+// verse that IS present but whose text is a stub next to the aligned Vulgate
+// verse (a likely truncation or lost line -- the one defect the count-based
+// checks cannot see) is likewise a warning.
 func CheckCorpus(code string) CorpusReport {
 	r := CorpusReport{Code: code}
 
@@ -62,6 +67,7 @@ func CheckCorpus(code string) CorpusReport {
 
 	ref := load("vul")
 	for book, chaps := range c.books {
+		refBook := ref.books[book] // nil if vul lacks the book (e.g. an EF-only name)
 		for ch, verses := range chaps {
 			seen := map[int]bool{}
 			maxV := 0
@@ -77,9 +83,35 @@ func CheckCorpus(code string) CorpusReport {
 			if maxV > len(seen) {
 				r.Warnings = append(r.Warnings, fmt.Sprintf("%s %d: verse gap (have %d verse(s), highest numbered %d)", book, ch, len(seen), maxV))
 			}
+
+			// Suspiciously-short verse: present, but a stub next to the SAME verse
+			// in the reference Vulgate -- a likely truncation or lost line (an
+			// opening dropped in a scrape, a merge artifact) that the
+			// presence-only checks cannot see, since the verse IS there. The
+			// comparison is cross-corpus, not within the chapter, precisely so a
+			// genuinely terse verse ("Non occides", "Jesus wept") is NOT flagged:
+			// the Vulgate's own copy is short too, so the guard below fails. It
+			// fires only when the corpus verse is a stub AND the aligned Vulgate
+			// verse is substantial. Skipped on the Psalms when the corpus
+			// renumbers them (psalm_system != vulgate), where the per-verse
+			// alignment with the Vulgate does not hold.
+			if refBook != nil && !(book == "Psalms" && m.PsalmSystem != "vulgate") {
+				if refCh, ok := refBook[ch]; ok {
+					refLen := make(map[int]int, len(refCh))
+					for _, rv := range refCh {
+						refLen[rv.Verse] = utf8.RuneCountInString(strings.TrimSpace(rv.Text))
+					}
+					for _, v := range verses {
+						n := utf8.RuneCountInString(strings.TrimSpace(v.Text))
+						if rl := refLen[v.Verse]; rl >= 40 && n < 12 && n*4 < rl {
+							r.Warnings = append(r.Warnings, fmt.Sprintf("%s %d:%d: text suspiciously short (%d chars vs vul %d)", book, ch, v.Verse, n, rl))
+						}
+					}
+				}
+			}
 		}
-		if refChaps, ok := ref.books[book]; ok {
-			for ch := range refChaps {
+		if refBook != nil {
+			for ch := range refBook {
 				if _, have := chaps[ch]; !have {
 					r.Warnings = append(r.Warnings, fmt.Sprintf("%s: missing chapter %d (present in vul)", book, ch))
 				}
diff --git a/internal/bible/validate_test.go b/internal/bible/validate_test.go
index 9cfec26..a3ed622 100644
--- a/internal/bible/validate_test.go
+++ b/internal/bible/validate_test.go
@@ -1,6 +1,9 @@
 package bible
 
-import "testing"
+import (
+	"strings"
+	"testing"
+)
 
 func TestCheckCorpus(t *testing.T) {
 	SetUserCorporaDir("testdata/corpora")
@@ -21,4 +24,18 @@ func TestCheckCorpus(t *testing.T) {
 	if r := CheckCorpus("badsystem"); r.OK() {
 		t.Fatal("bad psalm_system not caught")
 	}
+	// A verse present but a stub next to the Vulgate's (Genesis 1:1 = "x") is a
+	// warning, never an error -- the count-based checks can't see it.
+	if r := CheckCorpus("stub"); !hasWarning(r.Warnings, "suspiciously short") {
+		t.Fatalf("stub verse not warned; warnings: %v", r.Warnings)
+	}
+}
+
+func hasWarning(ws []string, substr string) bool {
+	for _, w := range ws {
+		if strings.Contains(w, substr) {
+			return true
+		}
+	}
+	return false
 }