feat(seo): implement dynamic metadata, sitemap, and robots.txt

Add dynamic meta tags for routes and entity detail pages
Generate sitemap.xml and robots.txt dynamically in Vite
Change default frontend port from 3000 to 20015

frontend/Dockerfile

@@ -6,5 +6,5 @@ RUN corepack enable && pnpm install
 COPY frontend/. .
 COPY package.json /app/package.json
 COPY system-wordings.ts /app/system-wordings.ts
-EXPOSE 3000
+EXPOSE 20015
 CMD ["pnpm", "run", "dev"]