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, 54 insertions, 28 deletions

diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index 4d172c0..b1f3ddd 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -4,8 +4,22 @@ import (
 	"os"
 	"path/filepath"
 	"testing"
+
+	"github.com/lukaszkasprzak/lectio/internal/bible"
 )
 
+// 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)
+	}
+}
+
 func TestLoadSeeds(t *testing.T) {
 	dir := t.TempDir()
 	t.Setenv("XDG_CONFIG_HOME", dir)
@@ -16,26 +30,32 @@ func TestLoadSeeds(t *testing.T) {
 	if cfg.DefaultVersion != "vul" || cfg.Offline {
 		t.Errorf("defaults wrong: %+v", cfg)
 	}
-	// Versions defaults to the corpora actually available in this build, Vulgate
-	// first then the rest sorted. Tests build with -tags fullbible, so all four
-	// are present (see Makefile); a default vul-only binary would list just vul.
-	wantVersions := []string{"vul", "drb", "grb", "wuj"}
-	if len(cfg.Versions) != len(wantVersions) {
-		t.Errorf("versions default = %v, want %v", cfg.Versions, wantVersions)
-	} else {
-		for i, v := range wantVersions {
-			if cfg.Versions[i] != v {
-				t.Errorf("versions default = %v, want %v", cfg.Versions, wantVersions)
-				break
-			}
-		}
-	}
 	if cfg.Lectionary != "new" {
 		t.Errorf("lectionary default wrong: %+v", cfg)
 	}
 	if _, err := os.Stat(filepath.Join(dir, "lectio", "config.ini")); err != nil {
 		t.Error("config not seeded")
 	}
+	// Versions defaults to the corpora actually available in this build, Vulgate
+	// first then the rest sorted. With -tags fullbible all four are present (see
+	// Makefile); a default vul-only binary would list just vul, so this
+	// assertion needs the optional corpora embedded.
+	t.Run("all corpora listed", func(t *testing.T) {
+		requireCorpus(t, "drb")
+		requireCorpus(t, "grb")
+		requireCorpus(t, "wuj")
+		wantVersions := []string{"vul", "drb", "grb", "wuj"}
+		if len(cfg.Versions) != len(wantVersions) {
+			t.Errorf("versions default = %v, want %v", cfg.Versions, wantVersions)
+		} else {
+			for i, v := range wantVersions {
+				if cfg.Versions[i] != v {
+					t.Errorf("versions default = %v, want %v", cfg.Versions, wantVersions)
+					break
+				}
+			}
+		}
+	})
 }
 
 // TestLoadMigratesBT checks a legacy config still carrying the retired "bt"
@@ -324,20 +344,26 @@ func TestPartShown(t *testing.T) {
 }
 
 func TestReadingCorpusResolution(t *testing.T) {
-	// drb is an embedded corpus with lang=en.
-	c := Config{ReadingVersion: "drb"}
-	if got := c.ReadingCorpus(); got != "drb" {
-		t.Fatalf("explicit reading_version: got %q", got)
-	}
-	c = Config{ReadingLang: "en"}
-	if got := c.ReadingCorpus(); got != "drb" {
-		t.Fatalf("reading_lang match: got %q", got)
-	}
-	c = Config{UILanguage: "en"}
-	if got := c.ReadingCorpus(); got != "drb" {
-		t.Fatalf("ui_language fallback: got %q", got)
-	}
-	c = Config{UILanguage: "pl"} // no pl corpus embedded
+	// The explicit-passthrough, reading_lang and ui_language cases all resolve to
+	// the embedded drb (lang=en) via bible.Meta/CorporaForLang, so they need drb.
+	t.Run("drb", func(t *testing.T) {
+		requireCorpus(t, "drb")
+		c := Config{ReadingVersion: "drb"}
+		if got := c.ReadingCorpus(); got != "drb" {
+			t.Fatalf("explicit reading_version: got %q", got)
+		}
+		c = Config{ReadingLang: "en"}
+		if got := c.ReadingCorpus(); got != "drb" {
+			t.Fatalf("reading_lang match: got %q", got)
+		}
+		c = Config{UILanguage: "en"}
+		if got := c.ReadingCorpus(); got != "drb" {
+			t.Fatalf("ui_language fallback: got %q", got)
+		}
+	})
+	// No pl corpus is autoselect-eligible, so pl resolves to "" on either build
+	// -- pure logic, keep it running.
+	c := Config{UILanguage: "pl"}
 	if got := c.ReadingCorpus(); got != "" {
 		t.Fatalf("no match should be empty: got %q", got)
 	}