perf: 预热扩展至最新页,串行错峰避免卡顿

预热列表新增「最新」(/browse?sort=latest)。三个预取改为串行执行:每个在空闲
(requestIdleCallback)时触发、间隔 400ms,避免并发请求拖卡低端手机。仅 JSON。

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/layouts/PublicLayout.tsx

@@ -294,29 +294,41 @@ export function PublicLayout() {
   // Current page name shown in the header brand slot (falls back to the brand).
   const pageTitle = usePageTitle();
 
-  // Warm "全部资料" and "热门资料" in the background (when idle) so tapping them
-  // shows content immediately instead of loading on arrival.
+  // Warm the common stream views (全部资料 / 热门资料 / 最新) in the background so
+  // tapping them shows content immediately. Run one at a time, spaced out and
+  // only while idle, so prefetching never competes with the current page or
+  // janks low-end phones. Prefetch is JSON-only (no images).
   useEffect(() => {
-    const run = () => {
-      const base = {
-        scope: { kind: "all" as const },
-        type: "all",
-        q: "",
-        lang,
-      };
-      prefetchPostStream({ ...base, sort: "" });
-      prefetchPostStream({ ...base, sort: "popular" });
-    };
+    const base = { scope: { kind: "all" as const }, type: "all", q: "", lang };
+    const jobs = [
+      () => prefetchPostStream({ ...base, sort: "" }),
+      () => prefetchPostStream({ ...base, sort: "popular" }),
+      () => prefetchPostStream({ ...base, sort: "latest" }),
+    ];
     const ric = window as typeof window & {
       requestIdleCallback?: (cb: () => void) => number;
       cancelIdleCallback?: (id: number) => void;
     };
-    if (ric.requestIdleCallback) {
-      const id = ric.requestIdleCallback(run);
-      return () => ric.cancelIdleCallback?.(id);
-    }
-    const id = window.setTimeout(run, 600);
-    return () => window.clearTimeout(id);
+
+    let i = 0;
+    let stepTimer = 0;
+    let idleId = 0;
+    const runNext = () => {
+      if (i >= jobs.length) return;
+      jobs[i++]();
+      stepTimer = window.setTimeout(schedule, 400); // space requests apart
+    };
+    const schedule = () => {
+      if (ric.requestIdleCallback) idleId = ric.requestIdleCallback(runNext);
+      else stepTimer = window.setTimeout(runNext, 200);
+    };
+
+    const startTimer = window.setTimeout(schedule, 600);
+    return () => {
+      window.clearTimeout(startTimer);
+      window.clearTimeout(stepTimer);
+      if (idleId) ric.cancelIdleCallback?.(idleId);
+    };
   }, [lang]);
   const popularHref = "/browse?sort=popular";