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/migration/src/lib.rs

@@ -44,6 +44,7 @@ mod m20260401_000033_add_taxonomy_metadata_and_media_assets;
 mod m20260401_000034_add_source_markdown_to_posts;
 mod m20260401_000035_add_human_verification_modes_to_site_settings;
 mod m20260402_000036_create_worker_jobs;
+mod m20260402_000037_add_wechat_share_qr_setting_to_site_settings;
 pub struct Migrator;
 
 #[async_trait::async_trait]
@@ -92,6 +93,7 @@ impl MigratorTrait for Migrator {
             Box::new(m20260401_000034_add_source_markdown_to_posts::Migration),
             Box::new(m20260401_000035_add_human_verification_modes_to_site_settings::Migration),
             Box::new(m20260402_000036_create_worker_jobs::Migration),
+            Box::new(m20260402_000037_add_wechat_share_qr_setting_to_site_settings::Migration),
             // inject-above (do not remove this comment)
         ]
     }