0.2.4-dev: round-29 community fixes and the official shared card pool

- Shared card pool and item stock as in the official mode (the owner's request, from the 路标档案馆 video and public notes): solo low-tier exceptions, co-op operators x2, shared item stock with special-item exceptions, normal / advanced occupancy 1 / 2, re-check on buy, 机变 exhaustion, release on consume / destroy / elimination; 整备 never exceeds stock; invariant held <= cap.
- 突袭: one taunt-first reselect right after a revive (the owner's rule); ordinary polls and redeploys keep the 0.2.3 rule; a revive on an enemy's tile stays. #475: online boss / hidden-boss Raid may land on the empty half (owner-limited scope).
- 浊心斯卡蒂 S1 x 坚守 no longer bounce redirected damage, and the two shares conserve the hit (idea of PR #464 by @HappyTanuki).
- Operator fixes adapted from PRs by @Xinglan233 (#459 哈洛德 S2 elemental trigger, #460 涤火杰西卡 shield on the four adjacent tiles, #461 家族徽章 first hit after stealth, #462 松果 S2 regrow per deploy); 克莱门莎 S2 splash 1.1 / 100% ATK and air auto-trigger (#467); 白面 copying 歌蕾蒂娅 / 余 skips the three-member condition (#473, the owner's video).
- 香槟炸弹 is not chosen by friendly auras / heals (PR #468 / #476 by @Siornya); 琳琅诗怀雅 coin balance (PR #450 by @IceCodeNew); Touch prep display (PR #451 by @YinqiMargatroid); lobby header (PR #471 by @YuriRestia); Japanese UI terms (PR #448 by @scutkane).
- AI-only boss countdown grace, render-failure cache / recovery without restarting a battle, device units kept on a same-field re-entry, DIY detail / skill previews, large-text result buttons.
- golden: battle families equal 0.2.3 except diy-135 / diy-136 (克莱门莎); all 18 release matches move through the shared pool, every flip named in docs/history/0.2.4.md §29.12; two coverage scenarios added.

public/js/render/board3d/load.js

@@ -16,10 +16,20 @@ import { parseObj } from './obj.js';
 export const THREE_URL = '/vendor/three.module.js';
 
 let threePromise = null;
+let threeFailures = 0;
 /** Dynamic import of the vendored three.js ESM build (browser only); null when unavailable. */
 export function loadThree(url = THREE_URL) {
   if (!threePromise) {
-    threePromise = import(/* @vite-ignore */ url).then((m) => (m && m.WebGLRenderer ? m : null), () => null);
+    // Browsers also cache failed module imports. Two bounded retry URLs permit a transient download failure to
+    // recover; clearing only our promise would keep receiving that same cached rejection without another request.
+    if (threeFailures >= 3) return Promise.resolve(null);
+    const source = new URL(url, import.meta.url);
+    if (threeFailures) source.searchParams.set('sp-retry', String(threeFailures));
+    const pending = import(/* @vite-ignore */ source.href).then((m) => (m && m.WebGLRenderer ? m : null), () => null).then((m) => {
+      if (!m && threePromise === pending) { threePromise = null; threeFailures++; }
+      return m;
+    });
+    threePromise = pending;
   }
   return threePromise;
 }
@@ -95,7 +105,7 @@ async function fetchJson(url) {
  */
 export function loadBoardPack(assets) {
   if (cached) return cached;
-  cached = (async () => {
+  const pending = (async () => {
     if (!assets || typeof assets.local !== 'function' || typeof assets.localUrl !== 'function' || typeof assets.image !== 'function') return null;
     const manifest = await assets.local().catch(() => null);
     if (!isObj(manifest)) return null;
@@ -106,7 +116,7 @@ export function loadBoardPack(assets) {
     await Promise.all(Object.entries(PACK_IMAGES).map(async ([k, [g, n]]) => {
       const u = url(g, n);
       if (!u) return;
-      const img = await assets.image(u).catch(() => null);
+      const img = await assets.image(u, { retry: true }).catch(() => null);
       if (img && (img.width || img.naturalWidth) > 0) images[k] = img;
     }));
     if (!images.D) return null;
@@ -138,9 +148,15 @@ export function loadBoardPack(assets) {
       images, meshes, tiles: isObj(tiles) ? tiles : null, uv: resolveUvTable(isObj(tiles) ? tiles : null),
       materials: { theme: isObj(theme) ? theme : null, fx: isObj(fxMats) ? fxMats : null },
     };
-  })().catch((err) => { console.warn('[board3d] art load failed', err); return null; });
-  return cached;
+  })().catch((err) => { console.warn('[board3d] art load failed', err); return null; }).then((pack) => {
+    // A timeout / failed atlas is not proof the host lacks 3D art. A later mount or visibility change may retry.
+    // An older attempt finishing after reset must not discard a newer cached request.
+    if (!pack && cached === pending) cached = null;
+    return pack;
+  });
+  cached = pending;
+  return pending;
 }
 
-/** Forget the cached pack (tests / hot reload). */
-export function resetBoardPack() { cached = null; threePromise = null; }
+/** Forget the cached pack and the three.js import attempt (tests / hot reload). */
+export function resetBoardPack() { cached = null; threePromise = null; threeFailures = 0; }