[SEO] Implement Comprehensive SEO with Open Graph, Structured Data, Sitemap, and Metadata

[Jokay1997]

Summary

Implements comprehensive SEO for the EquipChain frontend dashboard, including Open Graph tags, Twitter Cards, structured data (JSON-LD), sitemap generation, robots.txt, per-page metadata, and an Open Graph image placeholder.

Closes #23

Changes

Metadata Infrastructure

• src/lib/seo/metadata.ts — \generateMetadata({ title, description, path, image })\ helper with title template (%s | EquipChain), canonical URL, and base URL from \NEXT_PUBLIC_BASE_URL\ env var
• app/layout.tsx — Updated global metadata with:
  • Open Graph tags (og:title, og:description, og:image, og:url, og:type, og:site_name, og:locale)
  • Twitter Card tags (twitter:card, twitter:site, twitter:creator, twitter:title, twitter:description, twitter:image)
  • Robots meta tag (index, follow)
  • Dynamic metadataBase from env

Structured Data (JSON-LD)

• src/lib/seo/json-ld.ts — Schema.org structured data generators:
  • \webApplicationSchema()\ — WebApplication schema with app details
  • \organizationSchema()\ — Organization schema with contact info and social links
  • \�readcrumbListSchema(items)\ — BreadcrumbList schema generator

Per-Page Metadata

• app/page.tsx — Home page with WebApplication + Organization + BreadcrumbList schemas
• app/dashboard/page.tsx — Dashboard page with BreadcrumbList
• app/meters/page.tsx — Meters page with BreadcrumbList
• app/billing/page.tsx — Billing page with BreadcrumbList
• app/streams/page.tsx — Streams page with BreadcrumbList

Sitemap & Robots

• app/sitemap.ts — Dynamic sitemap.xml with routes: /, /dashboard, /meters, /billing, /streams (priorities 1.0–0.6)
• app/robots.ts — Allows all crawlers in production, disallows /admin/* and /api/*, references sitemap; disallows all in non-production

Assets

• public/og-image.png — Default Open Graph image placeholder (1200×630)

Verification

• ✅
  pm run build\ passes successfully
• All routes compile as static pages
• No test suite configured (no test script in package.json)