web: horizontal/vertical/interlinear display modes + web_display config

Adds a display-layout option to lectio-web alongside the existing colour
themes:

- config: WebDisplay field (toml web_display), default "horizontal",
  normalized on load via the new exported config.NormalizeDisplay
  (unknown -> "horizontal", same lenient style as the other web_* fields).
- render: extracts the citation/ToEnglishRef resolution shared by
  GatherVersion into an unexported resolveRef helper (GatherVersion's
  signature/behavior unchanged) and adds GatherVerses(version, sec,
  lectionary) returning raw bible.Verse structs plus a versified flag, for
  column/interlinear alignment.
- web/render: RenderReadings gains a display parameter. "horizontal" is
  the original stacked layout, byte-for-byte the same code path as
  before. "vertical" reuses the same per-version column data in a
  .display-vertical/.vcol grid (the CLI compare view, browser-side).
  "interlinear" maps versions through render.OfflineVersions' pl->wuj
  substitution (pl has no verse numbers), gathers GatherVerses per
  version, and interleaves them by chapter:verse into .ilverse/.illine
  blocks (ordered union of keys, first versified version's order first).
- server: adds a display <select> to the top bar wired into the existing
  #controls HTMX form; a resolveQuery(cfg, r) helper replaces the
  duplicated date/lectionary/all/versions(+now display) resolution in
  indexHandler and readingsHandler.
- fold-in from the B2 review: indexHandler now populates indexData.Lookup
  via a shared renderLookup(ref, versions) helper (also used by
  lookupHandler), so a bookmarked "/?ref=...&v=..." link shows its
  lookup result instead of an empty pane.
- base.css: layout-only rules for the two new modes (no colours; themes
  stay colour-only).

go test ./..., go vet ./..., gofmt clean; go build ./cmd/lectio-web ok.

1 files changed, 91 insertions, 0 deletions

diff --git a/internal/web/server_test.go b/internal/web/server_test.go
index 9e37177..b5cf78a 100644
--- a/internal/web/server_test.go
+++ b/internal/web/server_test.go
@@ -104,4 +104,95 @@ func TestServer(t *testing.T) {
 			t.Error("theme.css fallback served empty body")
 		}
 	})
+
+	t.Run("readings partial interlinear", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/readings?date=2026-07-22&v=wuj&v=vul&display=interlinear", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		body := rec.Body.String()
+		if strings.Contains(body, "<html") {
+			t.Errorf("partial is not a fragment: %q", body)
+		}
+		i := strings.Index(body, `class="vnum"`)
+		if i == -1 {
+			t.Fatalf("interlinear partial missing a vnum verse label: %q", body)
+		}
+		// Bound the first ilverse block by the next vnum span (each ilverse
+		// carries exactly one), so the check covers every version's line
+		// grouped under that one key, not just the first.
+		block := body[i:]
+		if j := strings.Index(body[i+1:], `class="vnum"`); j != -1 {
+			block = body[i : i+1+j]
+		}
+		if !strings.Contains(block, "Wujek") || !strings.Contains(block, "Wulgata") {
+			t.Errorf("interlinear verse block missing both version labels grouped together: %q", block)
+		}
+	})
+
+	t.Run("readings partial vertical", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/readings?date=2026-07-22&v=wuj&v=vul&display=vertical", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		if !strings.Contains(rec.Body.String(), "display-vertical") {
+			t.Errorf("vertical partial missing display-vertical: %q", rec.Body.String())
+		}
+	})
+
+	t.Run("readings partial interlinear substitutes pl", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/readings?date=2026-07-22&v=pl&display=interlinear", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		body := rec.Body.String()
+		if !strings.Contains(body, "Wujek") {
+			t.Errorf("pl should be substituted with wuj in interlinear mode: %q", body)
+		}
+		if strings.Contains(body, "Polski (niedziela.pl)") {
+			t.Errorf("pl paragraph column should not appear in interlinear mode: %q", body)
+		}
+	})
+
+	t.Run("readings partial bad display falls back to horizontal", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/readings?date=2026-07-22&v=wuj&display=bogus", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		body := rec.Body.String()
+		if strings.Contains(body, "display-vertical") || strings.Contains(body, "ilverse") {
+			t.Errorf("bad display should fall back to horizontal, got: %q", body)
+		}
+	})
+
+	t.Run("index page seeds lookup results from ?ref=", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/?ref=J+20:1&v=wuj", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		body := rec.Body.String()
+		if !strings.Contains(body, `id="lookup-results"`) {
+			t.Fatalf("body missing lookup-results container: %q", body)
+		}
+		i := strings.Index(body, `id="lookup-results"`)
+		if !strings.Contains(body[i:], "20:1") {
+			t.Errorf("lookup-results not populated from ?ref=: %q", body[i:min(i+400, len(body))])
+		}
+	})
+
+	t.Run("index page seeds display select from cfg", func(t *testing.T) {
+		rec := httptest.NewRecorder()
+		srv.ServeHTTP(rec, httptest.NewRequest("GET", "/?date=2026-07-22&v=wuj", nil))
+		if rec.Code != http.StatusOK {
+			t.Fatalf("status = %d, want 200", rec.Code)
+		}
+		if !strings.Contains(rec.Body.String(), `name="display"`) {
+			t.Errorf("body missing display select: %q", rec.Body.String())
+		}
+	})
 }