Card filter: show only Universes Beyond cards

The Universes Beyond toggle now cycles off → hide → only, backed by a new
only_universes_beyond library filter. Choosing "only" counts as a real
query, so Card Search runs it on its own.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/api.ts

@@ -201,6 +201,8 @@ export interface LibraryFilter {
    *  Warhammer 40,000, Marvel, …). Ordinary cards reprinted into a UB set are
    *  kept. Needs card data downloaded after this shipped; inert otherwise. */
   exclude_universes_beyond?: boolean;
+  /** The opposite: only cards that exist only as Universes Beyond. */
+  only_universes_beyond?: boolean;
   /** Hide Arena/MTGO-only cards (Alchemy rebalances) — they can't be owned on
    *  paper. Needs card data downloaded after this shipped; inert otherwise. */
   exclude_digital_only?: boolean;

src/components.tsx

@@ -2391,6 +2391,8 @@ const ICON_PACKAGE = icon(
  */
 export type CardCriteria = {
   excludeUb: boolean;
+  /** Never set together with `excludeUb`: the toggle cycles off → hide → only. */
+  onlyUb: boolean;
   excludeDigital: boolean;
   excludeFunny: boolean;
   priceMin: string;
@@ -2410,6 +2412,7 @@ export type CardCriteria = {
 
 export const EMPTY_CRITERIA: CardCriteria = {
   excludeUb: false,
+  onlyUb: false,
   excludeDigital: false,
   excludeFunny: false,
   priceMin: "",
@@ -2451,6 +2454,7 @@ const num = (s: string): number | null => (s.trim() === "" ? null : Number(s));
 export function applyCardCriteria(c: CardCriteria): Partial<LibraryFilter> {
   return {
     exclude_universes_beyond: c.excludeUb,
+    only_universes_beyond: c.onlyUb,
     exclude_digital_only: c.excludeDigital,
     exclude_funny: c.excludeFunny,
     price_min: num(c.priceMin),
@@ -2474,10 +2478,12 @@ export function applyCardCriteria(c: CardCriteria): Partial<LibraryFilter> {
  * The three "exclude" toggles deliberately don't count: they refine a result
  * set rather than select one, so ticking "hide Un-sets" on its own shouldn't
  * make Card Search pull every card in the database. Choosing a format, a
- * power range, or "not owned" is a real query, and does.
+ * power range, "not owned" or "only Universes Beyond" is a real query, and
+ * does.
  */
 export function criteriaActive(c: CardCriteria): boolean {
   return (
+    c.onlyUb ||
     c.canBeCommander ||
     c.vanillaOnly ||
     c.notOwned ||
@@ -2611,13 +2617,29 @@ export function CardCriteriaFields({
         <div className="icon-toggles">
           {/* Exclusions read as "no X" — tinted with the danger colour when
               active, so removing things looks different from selecting them. */}
+          {/* Three states: off → hide → only → off. "Only" looks like the
+              other "only" toggles rather than an exclusion. */}
           <IconToggle
             icon={ICON_CROSSOVER}
-            label="Hide Universes Beyond"
-            hint="Cards that only exist as another property — Lord of the Rings, Warhammer 40,000, Marvel. Normal cards reprinted in those sets stay."
-            exclude
-            on={c.excludeUb}
-            onToggle={() => onChange({ excludeUb: !c.excludeUb })}
+            label={
+              c.onlyUb
+                ? "Only Universes Beyond (click to show all)"
+                : c.excludeUb
+                  ? "Hiding Universes Beyond (click for only them)"
+                  : "Hide Universes Beyond"
+            }
+            hint="Cards that only exist as another property — Lord of the Rings, Warhammer 40,000, Marvel. Normal cards reprinted in those sets count as normal cards. Click again to show only these cards, and once more to show everything."
+            exclude={!c.onlyUb}
+            on={c.excludeUb || c.onlyUb}
+            onToggle={() =>
+              onChange(
+                c.onlyUb
+                  ? { excludeUb: false, onlyUb: false }
+                  : c.excludeUb
+                    ? { excludeUb: false, onlyUb: true }
+                    : { excludeUb: true, onlyUb: false },
+              )
+            }
           />
           <IconToggle
             icon={ICON_SCREEN}