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.

backend/src/controllers/site_settings.rs

@@ -157,6 +157,8 @@ pub struct SiteSettingsPayload {
     pub seo_default_og_image: Option<String>,
     #[serde(default, alias = "seoDefaultTwitterHandle")]
     pub seo_default_twitter_handle: Option<String>,
+    #[serde(default, alias = "seoWechatShareQrEnabled")]
+    pub seo_wechat_share_qr_enabled: Option<bool>,
     #[serde(default, alias = "notificationWebhookUrl")]
     pub notification_webhook_url: Option<String>,
     #[serde(default, alias = "notificationChannelType")]
@@ -212,6 +214,7 @@ pub struct PublicSiteSettingsResponse {
     pub subscription_popup_delay_seconds: i32,
     pub seo_default_og_image: Option<String>,
     pub seo_default_twitter_handle: Option<String>,
+    pub seo_wechat_share_qr_enabled: bool,
 }
 
 #[derive(Clone, Debug, Serialize)]
@@ -693,6 +696,9 @@ impl SiteSettingsPayload {
             item.seo_default_twitter_handle =
                 normalize_optional_string(Some(seo_default_twitter_handle));
         }
+        if let Some(seo_wechat_share_qr_enabled) = self.seo_wechat_share_qr_enabled {
+            item.seo_wechat_share_qr_enabled = Some(seo_wechat_share_qr_enabled);
+        }
         if let Some(notification_webhook_url) = self.notification_webhook_url {
             item.notification_webhook_url =
                 normalize_optional_string(Some(notification_webhook_url));
@@ -848,6 +854,7 @@ fn default_payload() -> SiteSettingsPayload {
         media_r2_secret_access_key: None,
         seo_default_og_image: None,
         seo_default_twitter_handle: None,
+        seo_wechat_share_qr_enabled: Some(false),
         notification_webhook_url: None,
         notification_channel_type: Some("webhook".to_string()),
         notification_comment_enabled: Some(false),
@@ -945,6 +952,7 @@ fn public_response(model: Model) -> PublicSiteSettingsResponse {
             .unwrap_or_else(default_subscription_popup_delay_seconds),
         seo_default_og_image: model.seo_default_og_image,
         seo_default_twitter_handle: model.seo_default_twitter_handle,
+        seo_wechat_share_qr_enabled: model.seo_wechat_share_qr_enabled.unwrap_or(false),
     }
 }