feat: 资料流标题+筛选吸顶,滚动时保持可见

把「全部资料」标题与筛选标签合并为一个吸顶块,钉在全局顶栏下方
(top-[64px]/md:top-[70px]),向下滚动时标题和筛选都不再消失,仅内容流滚动。
移除 FilterChips 原先吸到 top-0(藏到顶栏背后)的行为。

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

src/components/AssetStreamPage.tsx

@@ -1,7 +1,5 @@
-import { useEffect, useRef, useState } from "react";
 import type { PostScope } from "../types/post";
 import { MessageStream } from "./messageStream/MessageStream";
-import { SectionHeader } from "./SectionHeader";
 
 type AssetStreamPageProps = {
   title: string;
@@ -9,50 +7,9 @@ type AssetStreamPageProps = {
 };
 
 export function AssetStreamPage({ title, scope }: AssetStreamPageProps) {
-  // Telegram-style sticky page title: once the main heading scrolls up behind
-  // the global header, a floating pill slides in so users always know which
-  // page they're on.
-  const sentinelRef = useRef<HTMLDivElement>(null);
-  const [pinned, setPinned] = useState(false);
-
-  useEffect(() => {
-    const el = sentinelRef.current;
-    if (!el) return;
-    const io = new IntersectionObserver(
-      ([entry]) => setPinned(!entry.isIntersecting),
-      // Inset the top by the sticky header height so the pill appears exactly
-      // when the heading disappears behind it.
-      { rootMargin: "-64px 0px 0px 0px", threshold: 0 },
-    );
-    io.observe(el);
-    return () => io.disconnect();
-  }, []);
-
   return (
     <section>
-      <div className="mx-auto max-w-full px-4 md:max-w-[820px] lg:max-w-[1080px] xl:max-w-[1180px]">
-        <SectionHeader title={title} />
-      </div>
-      <div ref={sentinelRef} aria-hidden className="h-0" />
-
-      <div
-        className={`pointer-events-none fixed inset-x-0 top-[64px] z-30 flex justify-center px-4 transition-all duration-300 md:top-[70px] ${
-          pinned ? "translate-y-0 opacity-100" : "-translate-y-3 opacity-0"
-        }`}
-        aria-hidden={!pinned}
-      >
-        <div className="flex items-center gap-2 rounded-full border border-ark-line/80 bg-[#1c1c21]/90 px-4 py-1.5 shadow-lg shadow-black/40 backdrop-blur-md">
-          <span
-            className="h-3.5 w-[3px] shrink-0 rounded-full bg-ark-gold"
-            aria-hidden
-          />
-          <span className="truncate text-sm font-semibold text-white">
-            {title}
-          </span>
-        </div>
-      </div>
-
-      <MessageStream scope={scope} />
+      <MessageStream scope={scope} title={title} />
     </section>
   );
 }

src/components/messageStream/FilterChips.tsx

@@ -31,7 +31,7 @@ export function FilterChips({ type, onTypeChange }: FilterChipsProps) {
     ].join(" ");
 
   return (
-    <div className="sticky top-0 z-10 bg-ark-bg/95 backdrop-blur md:rounded-t-xl md:border-b md:border-ark-line">
+    <div className="bg-ark-bg/95 backdrop-blur md:rounded-t-xl">
       <div
         className="flex items-end gap-2 overflow-x-auto overflow-y-hidden px-4 pr-10 [-ms-overflow-style:none] [scrollbar-width:none] md:gap-5 md:px-1 md:pr-1 [&::-webkit-scrollbar]:hidden"
         role="tablist"

src/components/messageStream/MessageStream.tsx

@@ -6,15 +6,17 @@ import type { PostScope } from "../../types/post";
 import { Reveal } from "../../motion";
 import { Skeleton } from "../Skeleton";
 import { FilterChips } from "./FilterChips";
+import { SectionHeader } from "../SectionHeader";
 import { MessageBubble } from "./MessageBubble";
 import { useGroupedByDay } from "./hooks/useGroupedByDay";
 import { usePostStream } from "./hooks/usePostStream";
 
 export type MessageStreamProps = {
   scope: PostScope;
+  title?: string;
 };
 
-export function MessageStream({ scope }: MessageStreamProps) {
+export function MessageStream({ scope, title }: MessageStreamProps) {
   const { t, lang } = useI18n();
   const [sp, setSp] = useSearchParams();
   const { hash } = useLocation();
@@ -114,7 +116,16 @@ export function MessageStream({ scope }: MessageStreamProps) {
 
   return (
     <div className="mx-auto max-w-full md:max-w-[820px] lg:max-w-[1080px] xl:max-w-[1180px]">
+      {/* Title + filters stay pinned below the global header so users always
+          see which page they're on and can switch filters while scrolling. */}
+      <div className="sticky top-[64px] z-30 bg-ark-bg md:top-[70px]">
+        {title ? (
+          <div className="px-4 pb-1 pt-2 md:px-0">
+            <SectionHeader title={title} />
+          </div>
+        ) : null}
         <FilterChips type={type} onTypeChange={(v) => updateParam("type", v)} />
+      </div>
 
       <div className="flex flex-col gap-3 px-4 pt-4 md:px-0 md:pt-2">
         {isInitialLoad ? (