feat: add SharePanel component for social sharing with QR code support

- Implemented SharePanel component in `SharePanel.astro` for sharing content on social media platforms.
- Integrated QR code generation for WeChat sharing using the `qrcode` library.
- Added localization support for English and Chinese languages.
- Created utility functions in `seo.ts` for building article summaries and FAQs.
- Introduced API routes for serving IndexNow key and generating full LLM catalog and summaries.
- Enhanced SEO capabilities with structured data for articles and pages.

frontend/src/lib/api/client.ts

@@ -294,6 +294,7 @@ export interface ApiSiteSettings {
   subscription_popup_delay_seconds: number | null;
   seo_default_og_image: string | null;
   seo_default_twitter_handle: string | null;
+  seo_wechat_share_qr_enabled: boolean;
 }
 
 export interface ContentAnalyticsInput {
@@ -491,6 +492,7 @@ export const DEFAULT_SITE_SETTINGS: SiteSettings = {
   seo: {
     defaultOgImage: undefined,
     defaultTwitterHandle: undefined,
+    wechatShareQrEnabled: false,
   },
 };
 
@@ -509,6 +511,8 @@ const normalizePost = (post: ApiPost): UiPost => ({
   description: post.description,
   content: post.content,
   date: formatPostDate(post.created_at),
+  createdAt: post.created_at,
+  updatedAt: post.updated_at,
   readTime: estimateReadTime(post.content || post.description),
   type: post.post_type,
   tags: post.tags ?? [],
@@ -662,6 +666,7 @@ const normalizeSiteSettings = (settings: ApiSiteSettings): SiteSettings => {
   seo: {
     defaultOgImage: settings.seo_default_og_image ?? undefined,
     defaultTwitterHandle: settings.seo_default_twitter_handle ?? undefined,
+    wechatShareQrEnabled: Boolean(settings.seo_wechat_share_qr_enabled),
   },
   };
 };

frontend/src/lib/seo.ts

@@ -0,0 +1,276 @@
+import type { Post, SiteSettings } from './types';
+import { buildCategoryUrl, buildTagUrl } from './utils';
+
+export interface ArticleFaqItem {
+  question: string;
+  answer: string;
+}
+
+export interface DiscoveryFaqOptions {
+  locale: string;
+  pageTitle: string;
+  summary: string;
+  primaryUrl: string;
+  primaryLabel: string;
+  relatedLinks?: Array<{
+    label: string;
+    url: string;
+  }>;
+  signals?: string[];
+}
+
+function normalizeWhitespace(value: string): string {
+  return value.replace(/\s+/g, ' ').trim();
+}
+
+export function stripMarkdown(value: string): string {
+  return normalizeWhitespace(
+    value
+      .replace(/^---[\s\S]*?---/, ' ')
+      .replace(/!\[[^\]]*]\([^)]*\)/g, ' ')
+      .replace(/\[([^\]]+)]\([^)]*\)/g, '$1')
+      .replace(/`{1,3}[^`]*`{1,3}/g, ' ')
+      .replace(/^#{1,6}\s+/gm, '')
+      .replace(/^\s*[-*+]\s+/gm, '')
+      .replace(/^\s*\d+\.\s+/gm, '')
+      .replace(/[>*_~|]/g, ' ')
+  );
+}
+
+function truncate(value: string, maxLength: number): string {
+  if (value.length <= maxLength) {
+    return value;
+  }
+
+  return `${value.slice(0, Math.max(0, maxLength - 1)).trimEnd()}…`;
+}
+
+function uniqueNonEmpty(values: string[]): string[] {
+  const seen = new Set<string>();
+
+  return values.filter((value) => {
+    const normalized = normalizeWhitespace(value).toLowerCase();
+    if (!normalized || seen.has(normalized)) {
+      return false;
+    }
+
+    seen.add(normalized);
+    return true;
+  });
+}
+
+export function splitMarkdownParagraphs(value: string): string[] {
+  return value
+    .replace(/\r\n/g, '\n')
+    .split(/\n{2,}/)
+    .map((item) => stripMarkdown(item))
+    .map((item) => item.replace(/^#\s+/, '').trim())
+    .filter(Boolean);
+}
+
+function splitSentences(value: string): string[] {
+  return value
+    .split(/(?<=[。！？!?；;])\s*|(?<=\.)\s+/)
+    .map((item) => normalizeWhitespace(item))
+    .filter((item) => item.length >= 8);
+}
+
+export function buildArticleSynopsis(
+  post: Pick<Post, 'title' | 'description' | 'content'>,
+  maxLength = 220,
+): string {
+  const contentParagraphs = splitMarkdownParagraphs(post.content || '').filter(
+    (item) => normalizeWhitespace(item) !== normalizeWhitespace(post.title),
+  );
+  const parts = uniqueNonEmpty([post.description, ...contentParagraphs].filter(Boolean));
+
+  return truncate(parts.join(' '), maxLength);
+}
+
+export function buildArticleHighlights(
+  post: Pick<Post, 'title' | 'description' | 'content'>,
+  limit = 3,
+): string[] {
+  const paragraphs = splitMarkdownParagraphs(post.content || '').filter(
+    (item) => normalizeWhitespace(item) !== normalizeWhitespace(post.title),
+  );
+  const sentences = uniqueNonEmpty(
+    [post.description, ...paragraphs]
+      .filter(Boolean)
+      .flatMap((item) => splitSentences(item || '')),
+  );
+
+  return sentences.slice(0, limit).map((item) => truncate(item, 88));
+}
+
+export function resolvePostUpdatedAt(post: Pick<Post, 'updatedAt' | 'publishAt' | 'createdAt' | 'date'>): string {
+  return post.updatedAt || post.publishAt || post.createdAt || post.date;
+}
+
+export function buildArticleFaqs(
+  post: Pick<Post, 'title' | 'category' | 'tags'>,
+  options: {
+    locale: string;
+    summary: string;
+    readTimeMinutes: number;
+  },
+): ArticleFaqItem[] {
+  const isEnglish = options.locale.startsWith('en');
+  const tags = post.tags.slice(0, 5);
+  const keywordList = tags.length ? tags.join(isEnglish ? ', ' : '、') : post.category;
+  const categoryUrl = buildCategoryUrl(post.category);
+  const tagUrls = tags.slice(0, 2).map((tag) => buildTagUrl(tag));
+
+  const items = isEnglish
+    ? [
+        {
+          question: `What is "${post.title}" mainly about?`,
+          answer: options.summary,
+        },
+        {
+          question: 'What keywords or topics appear in this page?',
+          answer: `This page belongs to ${post.category} and highlights ${keywordList}. Estimated reading time is about ${Math.max(
+            options.readTimeMinutes,
+            1,
+          )} minute(s).`,
+        },
+        {
+          question: 'Where should I continue if I want related content?',
+          answer: `Start with the category page ${categoryUrl} and then continue with related tags ${tagUrls.join(
+            ', ',
+          ) || buildTagUrl('')}.`,
+        },
+      ]
+    : [
+        {
+          question: `《${post.title}》主要讲什么？`,
+          answer: options.summary,
+        },
+        {
+          question: '这页内容涉及哪些关键词？',
+          answer: `这篇内容归档在「${post.category}」，重点关键词包括 ${keywordList}，预计阅读时间约 ${Math.max(
+            options.readTimeMinutes,
+            1,
+          )} 分钟。`,
+        },
+        {
+          question: '如果想继续阅读相关内容，应该从哪里开始？',
+          answer: `建议先看分类页 ${categoryUrl}，再继续浏览相关标签 ${tagUrls.join('、') || buildTagUrl('')}。`,
+        },
+      ];
+
+  return items.map((item) => ({
+    question: truncate(item.question, 120),
+    answer: truncate(item.answer, 320),
+  }));
+}
+
+export function buildDiscoveryHighlights(values: string[], limit = 3, maxLength = 96): string[] {
+  return uniqueNonEmpty(values.map((item) => normalizeWhitespace(item)).filter(Boolean))
+    .slice(0, limit)
+    .map((item) => truncate(item, maxLength));
+}
+
+export function buildPageFaqs(options: DiscoveryFaqOptions): ArticleFaqItem[] {
+  const isEnglish = options.locale.startsWith('en');
+  const relatedLinks = (options.relatedLinks || []).slice(0, 3);
+  const relatedText = relatedLinks
+    .map((item) => `${item.label}: ${item.url}`)
+    .join(isEnglish ? '; ' : '；');
+  const signalText = uniqueNonEmpty(options.signals || []).join(isEnglish ? ', ' : '、');
+
+  const items = isEnglish
+    ? [
+        {
+          question: `What is the main purpose of "${options.pageTitle}"?`,
+          answer: options.summary,
+        },
+        {
+          question: 'Which URL should be cited as the canonical source?',
+          answer: `Use ${options.primaryLabel} as the canonical page: ${options.primaryUrl}.`,
+        },
+        {
+          question: 'Where should I continue for related information?',
+          answer: relatedText || signalText
+            ? `Continue with ${relatedText || signalText}.`
+            : `Continue from the canonical page ${options.primaryUrl}.`,
+        },
+      ]
+    : [
+        {
+          question: `「${options.pageTitle}」这一页的核心作用是什么？`,
+          answer: options.summary,
+        },
+        {
+          question: '这一页应该引用哪个规范地址？',
+          answer: `优先引用 ${options.primaryLabel} 的规范地址：${options.primaryUrl}。`,
+        },
+        {
+          question: '如果要继续浏览相关内容，应该看哪里？',
+          answer: relatedText || signalText
+            ? `建议继续查看：${relatedText || signalText}。`
+            : `建议从这个规范页继续展开：${options.primaryUrl}。`,
+        },
+      ];
+
+  return items.map((item) => ({
+    question: truncate(item.question, 120),
+    answer: truncate(item.answer, 320),
+  }));
+}
+
+export function buildFaqJsonLd(faqs: ArticleFaqItem[]) {
+  if (!faqs.length) {
+    return undefined;
+  }
+
+  return {
+    '@context': 'https://schema.org',
+    '@type': 'FAQPage',
+    mainEntity: faqs.map((item) => ({
+      '@type': 'Question',
+      name: item.question,
+      acceptedAnswer: {
+        '@type': 'Answer',
+        text: item.answer,
+      },
+    })),
+  };
+}
+
+export function buildPostItemList(posts: Post[], siteUrl: string) {
+  return posts.map((post, index) => ({
+    '@type': 'ListItem',
+    position: index + 1,
+    url: new URL(`/articles/${post.slug}`, siteUrl).toString(),
+    name: post.title,
+    description: post.description,
+  }));
+}
+
+export function buildPageTrackerLabel(referrer: string | null | undefined): string {
+  const source = normalizeWhitespace(referrer || '').toLowerCase();
+  if (!source) {
+    return 'direct';
+  }
+
+  if (source.includes('chatgpt') || source.includes('openai')) return 'chatgpt-search';
+  if (source.includes('perplexity')) return 'perplexity';
+  if (source.includes('copilot') || source.includes('bing')) return 'copilot-bing';
+  if (source.includes('gemini')) return 'gemini';
+  if (source.includes('google')) return 'google';
+  if (source.includes('claude')) return 'claude';
+  if (source.includes('duckduckgo')) return 'duckduckgo';
+  if (source.includes('kagi')) return 'kagi';
+
+  return source;
+}
+
+export function buildSiteTopicSummary(siteSettings: SiteSettings): string[] {
+  return uniqueNonEmpty([
+    siteSettings.siteDescription,
+    siteSettings.heroSubtitle,
+    siteSettings.ownerBio,
+    ...siteSettings.techStack.slice(0, 6).map((item) => `${siteSettings.siteName} covers ${item}`),
+  ]).slice(0, 4);
+}

frontend/src/lib/types/index.ts

@@ -5,6 +5,8 @@ export interface Post {
   description: string;
   content?: string;
   date: string;
+  createdAt?: string;
+  updatedAt?: string;
   readTime: string;
   type: 'article' | 'tweet';
   tags: string[];
@@ -105,6 +107,7 @@ export interface SiteSettings {
   seo: {
     defaultOgImage?: string;
     defaultTwitterHandle?: string;
+    wechatShareQrEnabled: boolean;
   };
 }