新增 OIDC/SSO、邮件验证码与 Gitea 项目同步，并强化 Feed 与管理后台。

作为 OIDC Provider 对接 Gitea；注册支持邮件验证码/验证码；侧栏同步公开仓库；Feed 分页、文章大纲、标签云与站点品牌设置。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/hooks/useSiteBranding.ts

@@ -0,0 +1,92 @@
+import { useEffect, useState } from 'react';
+import { api } from '../api/client';
+import type { SiteBranding } from '../api/types';
+
+export const DEFAULT_BRANDING: SiteBranding = {
+  name: '姜十三论坛',
+  name_en: 'Jiang13 Forum',
+  slogan: '拾三一隅，自在交流',
+  logo_mark: '姜',
+  logo: '',
+  favicon: '',
+};
+
+let cached: SiteBranding | null = null;
+let inflight: Promise<SiteBranding> | null = null;
+let cacheEpoch = 0;
+const listeners = new Set<() => void>();
+
+function fetchBranding(): Promise<SiteBranding> {
+  if (cached) return Promise.resolve(cached);
+  if (inflight) return inflight;
+  inflight = api.siteBranding()
+    .then(b => {
+      cached = { ...DEFAULT_BRANDING, ...b };
+      return cached;
+    })
+    .catch(() => cached ?? DEFAULT_BRANDING)
+    .finally(() => { inflight = null; });
+  return inflight;
+}
+
+function applyDocumentBrand(brand: SiteBranding) {
+  const title = brand.name_en ? `${brand.name} ${brand.name_en}` : brand.name;
+  if (document.title !== title) document.title = title;
+
+  let link = document.querySelector<HTMLLinkElement>('link[rel="icon"]');
+  if (brand.favicon) {
+    if (!link) {
+      link = document.createElement('link');
+      link.rel = 'icon';
+      document.head.appendChild(link);
+    }
+    if (link.href !== new URL(brand.favicon, window.location.origin).href) {
+      link.href = brand.favicon;
+    }
+  }
+}
+
+/** 获取站点品牌配置（名称、Logo 等） */
+export function useSiteBranding() {
+  const [branding, setBranding] = useState<SiteBranding>(cached ?? DEFAULT_BRANDING);
+  const [loading, setLoading] = useState(!cached);
+  const [epoch, setEpoch] = useState(cacheEpoch);
+
+  useEffect(() => {
+    const onInvalidate = () => setEpoch(cacheEpoch);
+    listeners.add(onInvalidate);
+    return () => { listeners.delete(onInvalidate); };
+  }, []);
+
+  useEffect(() => {
+    let cancelled = false;
+    if (!cached) setLoading(true);
+    fetchBranding()
+      .then(next => {
+        if (cancelled) return;
+        setBranding(next);
+        applyDocumentBrand(next);
+      })
+      .finally(() => {
+        if (!cancelled) setLoading(false);
+      });
+    return () => { cancelled = true; };
+  }, [epoch]);
+
+  return { branding, loading };
+}
+
+/** 清除缓存并通知已挂载的 hook 重新拉取 */
+export function invalidateSiteBrandingCache() {
+  cached = null;
+  cacheEpoch += 1;
+  listeners.forEach(fn => fn());
+}
+
+/** 用管理端刚保存的值立即更新缓存与文档标题 */
+export function seedSiteBrandingCache(brand: SiteBranding) {
+  cached = { ...DEFAULT_BRANDING, ...brand };
+  applyDocumentBrand(cached);
+  cacheEpoch += 1;
+  listeners.forEach(fn => fn());
+}