test(bible): skip corpus-dependent tests when optional corpora aren't embedded

Since 51c0f4e split the corpora (only vul embedded by default; wuj/drb/grb
behind -tags fullbible), `go test ./...` on the default build was red across six
packages -- every failure was a test assuming an optional corpus is present.

Guard those assertions with a skip keyed on bible.Meta(code), so they run under
-tags fullbible and skip -- not fail -- on the default vul-only build. Mixed
tests are split into subtests so the always-embedded vul assertions and pure
logic (pl->vul fallback, explicit passthrough, bt-rejection, i18n labels) keep
running on both builds. Test-only change; no product code or corpora touched.

- internal/bible: TestVerses, TestLookup, TestCorpusBooks, TestChapters,
  TestGrbNoApparatusMarkers, TestCrossChapterRange* (requireCorpus helper).
- internal/cli, config, render, tui, web: the same pattern for their
  corpus-dependent tests.
- Fixes an index-out-of-range panic in internal/tui's reader tests that was
  aborting the package binary and masking 3 further corpus-absence failures
  (TestReaderBookmarkFlow, TestReaderChapterJump, TestReaderRemembersPlace).

Verified: `go test ./...` and `go test -tags fullbible ./...` both green (0 FAIL);
guards active only on the default build (29 skips vs 1 unrelated pre-existing);
gofmt and go vet clean.

1 files changed, 26 insertions, 5 deletions

diff --git a/internal/cli/liturgy_test.go b/internal/cli/liturgy_test.go
index 67303f3..88a8b3d 100644
--- a/internal/cli/liturgy_test.go
+++ b/internal/cli/liturgy_test.go
@@ -57,14 +57,35 @@ func TestRunLiturgyTraditionalComputesEF(t *testing.T) {
 }
 
 func TestVernacularVersionResolver(t *testing.T) {
-	if got := vernacularVersion(config.Config{ReadingVersion: "drb"}); got != "drb" {
-		t.Fatalf("explicit: %q", got)
-	}
+	// pl has no autoselect-eligible corpus (the built-in Wujek sets
+	// autoselect=false), so Polish always falls back to Latin regardless of
+	// which optional corpora are embedded -- pure logic, keep it running.
 	if got := vernacularVersion(config.Config{UILanguage: "pl"}); got != "vul" {
 		t.Fatalf("pl should fall back to Latin: %q", got)
 	}
-	if got := vernacularVersion(config.Config{UILanguage: "en"}); got != "drb" {
-		t.Fatalf("en should be drb: %q", got)
+	// Both the explicit reading_version passthrough and the en->drb autoselect
+	// resolve through bible.Meta("drb") (Config.ReadingCorpus), so they need the
+	// optional drb corpus embedded.
+	t.Run("drb", func(t *testing.T) {
+		requireCorpus(t, "drb")
+		if got := vernacularVersion(config.Config{ReadingVersion: "drb"}); got != "drb" {
+			t.Fatalf("explicit: %q", got)
+		}
+		if got := vernacularVersion(config.Config{UILanguage: "en"}); got != "drb" {
+			t.Fatalf("en should be drb: %q", got)
+		}
+	})
+}
+
+// requireCorpus skips the test when corpus `code` is not embedded in this
+// build. The optional corpora (wuj, drb, grb) compile in only with
+// `-tags fullbible` (or when dropped into the user corpora dir); mirrors the
+// helper in internal/bible so these tests run under fullbible and skip -- not
+// fail -- on the default vul-only build.
+func requireCorpus(t *testing.T, code string) {
+	t.Helper()
+	if _, ok := bible.Meta(code); !ok {
+		t.Skipf("corpus %q not embedded; build with -tags fullbible", code)
 	}
 }