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, 48 insertions, 0 deletions

diff --git a/internal/web/static/base.css b/internal/web/static/base.css
index f99b4b5..220badd 100644
--- a/internal/web/static/base.css
+++ b/internal/web/static/base.css
@@ -144,6 +144,51 @@ body {
   margin-right: 0.35em;
 }
 
+/* Vertical display: versions side by side in columns, like the CLI
+ * `compare` view. A fixed --vcols track count (not auto-fit) means the
+ * grid's total width is always the page container's, so it wraps extra
+ * versions onto further rows instead of ever forcing horizontal scroll. */
+.display-vertical {
+  display: grid;
+  grid-template-columns: repeat(var(--vcols, 2), 1fr);
+  gap: var(--space-3) var(--space-4);
+  align-items: start;
+}
+
+.vcol {
+  min-width: 0;
+}
+
+/* Interlinear display: one .ilverse block per chapter:verse key, one
+ * .illine per version that carries it. */
+.display-interlinear {
+  display: flex;
+  flex-direction: column;
+}
+
+.ilverse {
+  margin: 0 0 var(--space-3);
+  padding-top: var(--space-1);
+  border-top-width: 1px;
+  border-top-style: solid;
+}
+
+.ilverse:first-child {
+  border-top-width: 0;
+  padding-top: 0;
+}
+
+.illine {
+  margin: 0.2rem 0 0.2rem var(--space-2);
+}
+
+.illine .version-label {
+  display: inline;
+  margin: 0 0.5em 0 0;
+  padding-bottom: 0;
+  border-bottom-width: 0;
+}
+
 a {
   text-decoration: underline;
   text-underline-offset: 0.15em;
@@ -160,4 +205,7 @@ a {
   .heading {
     font-size: 1.25rem;
   }
+  .display-vertical {
+    grid-template-columns: 1fr;
+  }
 }