Add 13 frontend guides and cross-link existing framework guides

[sarahkb125]

Summary

• Add 13 new guides tagged frontend: SPA routing, env variables, SSR/SSG/ISR, streaming AI responses, Socket.IO, authentication, full-stack Next.js, Strapi, Payload CMS, Ghost, Supabase, Gatsby, TanStack Start
• Add frontend tag to 5 existing guides (SSE vs WebSockets, static hosting, PR environments, CDN, Caddy)
• Add cross-links from 9 existing framework guides to new architecture guides
• Add Gatsby and TanStack Start to sidebar and languages-frameworks index

New files

• content/guides/spa-routing-configuration.md — Configure Caddy/Nginx for SPA client-side routing
• content/guides/frontend-environment-variables.md — Build-time vs runtime env vars across frameworks
• content/guides/ssr-ssg-isr.md — Decision guide for rendering strategies
• content/guides/streaming-ai-responses.md — Stream LLM tokens via SSE
• content/guides/socketio.md — Deploy Socket.IO with Redis adapter for scaling
• content/guides/frontend-authentication.md — Auth patterns (Clerk, Supabase Auth, session-based)
• content/guides/fullstack-nextjs.md — Next.js + Postgres + workers + file uploads
• content/guides/strapi.md — Self-host Strapi with Postgres
• content/guides/payload-cms.md — Self-host Payload CMS 3.x inside Next.js
• content/guides/ghost.md — Self-host Ghost with MySQL
• content/guides/supabase.md — Self-host the Supabase stack
• content/guides/gatsby.md — Deploy Gatsby static sites
• content/guides/tanstack-start.md — Deploy TanStack Start full-stack apps

Modified files

• content/docs/languages-frameworks.md — added Gatsby, TanStack Start
• src/data/sidebar.ts — added Gatsby, TanStack Start
• 5 guides — added frontend tag
• 9 framework guides — added cross-links to new architecture guides

Test plan

• Verify all 13 new guides render at /guides/<slug>
• Verify Gatsby and TanStack Start appear in sidebar under JS/TS
• Verify frontend tag filter on /guides shows all tagged guides
• Check all internal links resolve

🤖 Generated with Claude Code

[railway-app]

🚅 Deployed to the docs-pr-1117 environment in 🪄 *.railway.com

Service	Status	Web	Updated (UTC)
Docs Frontend	✅ Success (View Logs)	Web	Apr 14, 2026 at 2:58 pm

6 services not affected by this PR

• devicons
• OG
• Geofeed
• Frontend Redis
• Blog
• Turnout