feat(profile): pinned_papers 支持 Zotero itemKey 运行时填充

- UserPaperItem 加 itemKey 字段（可选）
- page.tsx 提取所有 itemKey 批量调 /api/user-center/zotero/items，
  Zotero 拉到的元信息作为主数据源，手填字段作为离线 fallback
- EditProfileForm papers 区增加 itemKey 输入框（提示可选），保存条件放宽为 itemKey 或 title 至少有一个
- 完全向后兼容：历史 pinned_papers（只有 title/authors 的）照常渲染

配套后端 commit involutionhell-backend 1fb697f（Zotero API 代理 + Caffeine 1h）

V2 全部完成：#1 编辑页 / #2 docs/history 迁 Java / #3 活跃度热力图 /
#4 关注系统 / #5 GitHub repos 同步 / #6 保留 analyticsEvent / #7 Zotero itemKey

Author: longsizhuo

app/u/[username]/edit/EditProfileForm.tsx

@@ -18,6 +18,8 @@ interface ProjectItem {
 }
 
 interface PaperItem {
+  /** Zotero group item key；填了之后 profile 页会自动拉 Zotero 元信息填充 */
+  itemKey: string;
   title: string;
   authors: string;
   year: string;
@@ -77,6 +79,7 @@ function normalize(raw: unknown): Preferences {
       : [],
     pinned_papers: Array.isArray(p.pinned_papers)
       ? p.pinned_papers.map((x) => ({
+          itemKey: x?.itemKey ?? "",
           title: x?.title ?? "",
           authors: x?.authors ?? "",
           year: String(x?.year ?? ""),
@@ -153,7 +156,8 @@ export function EditProfileForm({ targetIdentifier }: Props) {
       tagline: prefs.tagline,
       links: prefs.links.filter((l) => l.label && l.url),
       projects: prefs.projects.filter((p) => p.title),
-      pinned_papers: prefs.pinned_papers.filter((p) => p.title),
+      // 有 itemKey 或有 title 的条目保留，至少得有一个标识符
+      pinned_papers: prefs.pinned_papers.filter((p) => p.itemKey || p.title),
     };
     try {
       const res = await fetch("/api/user-center/preferences", {
@@ -328,6 +332,7 @@ export function EditProfileForm({ targetIdentifier }: Props) {
           items={prefs.pinned_papers}
           onChange={(items) => setPrefs({ ...prefs, pinned_papers: items })}
           empty={{
+            itemKey: "",
             title: "",
             authors: "",
             year: "",
@@ -337,6 +342,13 @@ export function EditProfileForm({ targetIdentifier }: Props) {
           maxItems={8}
           render={(item, idx, update) => (
             <div className="flex flex-col gap-2">
+              <input
+                type="text"
+                value={item.itemKey}
+                onChange={(e) => update({ ...item, itemKey: e.target.value })}
+                placeholder="Zotero itemKey（可选，填了会自动拉元信息；不填就手填下面字段）"
+                className="border border-dashed border-[var(--foreground)] bg-[var(--background)] px-3 py-2 font-mono text-xs uppercase tracking-wider"
+              />
               <input
                 type="text"
                 value={item.title}

app/u/[username]/page.tsx

@@ -28,13 +28,54 @@ interface UserProjectItem {
 }
 
 interface UserPaperItem {
-  title: string;
+  /** Zotero group item key；有值时优先从后端 /api/user-center/zotero/items 拉元信息 */
+  itemKey?: string;
+  title?: string;
   authors?: string;
   year?: string | number;
   url?: string;
   abstract?: string;
 }
 
+interface ZoteroItemDto {
+  itemKey: string;
+  title: string;
+  authors: string;
+  year: string;
+  url: string;
+  abstractNote: string;
+  publicationTitle: string;
+}
+
+/**
+ * 批量调后端 Zotero 代理，返回 itemKey → 元信息映射。
+ * 任意失败或没 itemKey 时返回空 map，调用方走手填 fallback。
+ */
+async function fetchZoteroByKeys(
+  keys: string[],
+): Promise<Record<string, ZoteroItemDto>> {
+  if (keys.length === 0) return {};
+  const backendUrl = process.env.BACKEND_URL;
+  if (!backendUrl) return {};
+  try {
+    const res = await fetch(
+      `${backendUrl}/api/user-center/zotero/items?keys=${encodeURIComponent(keys.join(","))}`,
+      { next: { revalidate: 3600 } },
+    );
+    if (!res.ok) return {};
+    const json = (await res.json()) as {
+      success: boolean;
+      data?: ZoteroItemDto[];
+    };
+    if (!json.success || !Array.isArray(json.data)) return {};
+    const map: Record<string, ZoteroItemDto> = {};
+    for (const it of json.data) map[it.itemKey] = it;
+    return map;
+  } catch {
+    return {};
+  }
+}
+
 interface UserLinkItem {
   label: string;
   url: string;
@@ -139,9 +180,28 @@ export default async function UserProfilePage({ params }: Param) {
     user.githubId,
   );
   const projects = preferences.projects ?? [];
-  const papers = preferences.pinned_papers ?? [];
+  const rawPapers = preferences.pinned_papers ?? [];
   const links = preferences.links ?? [];
 
+  // 用 itemKey 批量拉 Zotero 元信息 → 用它填字段，覆盖手填值（手填作为离线 fallback）
+  const zoteroKeys = rawPapers
+    .map((p) => p.itemKey)
+    .filter((k): k is string => typeof k === "string" && k.length > 0);
+  const zoteroMap = await fetchZoteroByKeys(zoteroKeys);
+  const papers: UserPaperItem[] = rawPapers.map((p) => {
+    if (!p.itemKey) return p;
+    const z = zoteroMap[p.itemKey];
+    if (!z) return p; // Zotero 拉不到就用手填值兜底
+    return {
+      itemKey: p.itemKey,
+      title: p.title || z.title,
+      authors: p.authors || z.authors,
+      year: p.year || z.year,
+      url: p.url || z.url,
+      abstract: p.abstract || z.abstractNote,
+    };
+  });
+
   return (
     <>
       <Header />