fix(liveness): eager-probe hide-until-verified cards (fixes vanished foreign feed)

Setting CARD_LIVENESS_POLICY=hide-foreign made all foreign/NIP-71 content
disappear: a hide-until-verified card starts display:none, which has no layout
box, so the IntersectionObserver never fires for it — its liveness probe never
runs, it never gets a healthy verdict, and it stays hidden forever (deadlock).

Fix: cardNeedsEagerLivenessProbe() identifies cards governed by a
hide-until-verified policy (foreign under hide-foreign; all non-owner under
hide-all). Both health observers now kick the probe for those cards from
onCardRegister — which fires for every card regardless of visibility — instead of
waiting for an intersection that a hidden card can never produce. The URL probe is
deferred one microtask so attachUrlHealthBadges has wired state.onCheck after
observe(). Probes stay concurrency-capped + priority-ordered; show-pending is
unchanged (no eager probing).

Tests: cardNeedsEagerLivenessProbe predicate coverage in
tests/video-card-source-visibility.test.mjs.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

js/urlHealthObserver.js

@@ -2,6 +2,7 @@ import { createCardObserver } from "./dom/cardObserver.js";
 import { safeDecodeURIComponent } from "./utils/safeDecode.js";
 import { userLogger } from "./utils/logger.js";
 import { getLivenessProbePrefetchMargin } from "./constants.js";
+import { cardNeedsEagerLivenessProbe } from "./utils/cardSourceVisibility.js";
 
 // Prefetch margin lets cards just below the fold start probing before they scroll
 // into view, so they're verified by the time the user reaches them.
@@ -20,44 +21,58 @@ const urlCardObserver = createCardObserver({
     return isIntersecting && ratio > 0;
   },
   createState: () => ({ onCheck: null }),
-  onCardVisible: ({ card, state }) => {
-    if (!state || typeof state.onCheck !== "function") {
-      return;
-    }
-
-    const badgeEl = card.querySelector("[data-url-health-state]");
-    if (!(badgeEl instanceof HTMLElement)) {
-      return;
-    }
-
-    const encodedUrl =
-      card.dataset.urlHealthUrl || badgeEl.dataset.urlHealthUrl || "";
-    const eventId =
-      card.dataset.urlHealthEventId || badgeEl.dataset.urlHealthEventId || "";
-
-    if (!encodedUrl || !eventId) {
-      return;
-    }
-
-    const currentState =
-      card.dataset.urlHealthState || badgeEl.dataset.urlHealthState;
-    if (currentState && currentState !== "checking") {
-      return;
-    }
-
-    const url = safeDecodeURIComponent(encodedUrl);
-    if (!url) {
-      return;
-    }
-
-    try {
-      state.onCheck({ card, badgeEl, url, eventId });
-    } catch (err) {
-      userLogger.warn("[urlHealthObserver] onCheck handler failed", err);
+  // Hide-until-verified cards start `display:none`, so the IntersectionObserver
+  // never fires for them — kick the URL probe eagerly on register so they can be
+  // verified and revealed (the alternative is they stay hidden forever).
+  onCardRegister: ({ card, state }) => {
+    if (cardNeedsEagerLivenessProbe(card)) {
+      // attachUrlHealthBadges sets state.onCheck right AFTER observe() returns, so
+      // defer one microtask to let that wiring land before we probe.
+      queueMicrotask(() => triggerUrlCheck(card, state));
     }
   },
+  onCardVisible: ({ card, state }) => {
+    triggerUrlCheck(card, state);
+  },
 });
 
+function triggerUrlCheck(card, state) {
+  if (!state || typeof state.onCheck !== "function") {
+    return;
+  }
+
+  const badgeEl = card.querySelector("[data-url-health-state]");
+  if (!(badgeEl instanceof HTMLElement)) {
+    return;
+  }
+
+  const encodedUrl =
+    card.dataset.urlHealthUrl || badgeEl.dataset.urlHealthUrl || "";
+  const eventId =
+    card.dataset.urlHealthEventId || badgeEl.dataset.urlHealthEventId || "";
+
+  if (!encodedUrl || !eventId) {
+    return;
+  }
+
+  const currentState =
+    card.dataset.urlHealthState || badgeEl.dataset.urlHealthState;
+  if (currentState && currentState !== "checking") {
+    return;
+  }
+
+  const url = safeDecodeURIComponent(encodedUrl);
+  if (!url) {
+    return;
+  }
+
+  try {
+    state.onCheck({ card, badgeEl, url, eventId });
+  } catch (err) {
+    userLogger.warn("[urlHealthObserver] onCheck handler failed", err);
+  }
+}
+
 export function attachUrlHealthBadges(container, onCheck) {
   if (!(container instanceof HTMLElement)) {
     return;