PR Checklist

No linked issue.

What is the new behavior?

• Adds a source-only @limitless-angular/analog-sanity-blog package that exposes the blog schema, GROQ queries, demo data, env helper, Presentation config, and Studio structure through package exports.
• Adds apps/analog-sanity-blog-studio as a real Sanity Studio for the Analog blog example, including setup, CORS, seed, schema extraction, typegen, dev, build, and serve workflows.
• Refactors the Analog blog example to consume the shared package, add Studio URL env support, regenerate Sanity types, and wire root Turbo scripts/docs/CI around the new workflow.
• Separates the Sanity env contracts by owner:
  • the Analog frontend keeps app runtime env in apps/analog-sanity-blog-example/.env.local
  • the blog Studio uses SANITY_STUDIO_* in apps/analog-sanity-blog-studio/.env.local
  • the Presentation E2E harness uses SANITY_E2E_* in apps/sanity-presentation-e2e/.env.local and CI
• Removes compatibility fallbacks from Studio/E2E code for old VITE_SANITY_* and SANITY_API_* names, while still mapping into the Analog app's runtime env internally when E2E starts the preview app.
• Uses Node 22 loadEnvFile for local env loading and tightens Turbo env pass-through/cache inputs around the new namespaces.

Does this PR introduce a breaking change?

• Yes
• No

The env-name changes apply to the new Studio/E2E workflows introduced by this PR. Existing application runtime env names remain unchanged.

Other information

Testing

• pnpm blog:typegen
• pnpm turbo run lint --filter=analog-sanity-blog-example --filter=analog-sanity-blog-studio
• pnpm exec eslint packages/analog-sanity-blog
• pnpm turbo run build --filter=analog-sanity-blog-example --filter=analog-sanity-blog-studio
• pnpm --filter=analog-sanity-blog-example exec tsc --noEmit --project tsconfig.app.json
• pnpm -C apps/analog-sanity-blog-studio run schema:extract && pnpm -C apps/analog-sanity-blog-studio exec sanity schema validate
• git diff --check
• pnpm turbo run lint --filter=analog-sanity-blog-studio --filter=sanity-presentation-e2e --filter=sanity-presentation-e2e-studio
• pnpm turbo run e2e --filter=sanity-presentation-e2e
• pnpm turbo run e2e-studio --filter=sanity-presentation-e2e
• pnpm turbo run build --filter=analog-sanity-blog-studio --filter=sanity-presentation-e2e-studio
• SANITY_E2E_STUDIO_MODE=real-project pnpm --dir=apps/sanity-presentation-e2e exec playwright test real-studio.spec.ts --list confirms real-project mode now fails fast on missing SANITY_E2E_PROJECT_ID
• PR CI is green on the latest branch, including main, presentation-e2e, autofix, and Sanity compatibility jobs.

Post-Deploy Monitoring & Validation

• For local setup, keep apps/analog-sanity-blog-example/.env.local for frontend runtime env, add apps/analog-sanity-blog-studio/.env.local for SANITY_STUDIO_*, and add apps/sanity-presentation-e2e/.env.local for SANITY_E2E_*.
• If deploying the blog Studio, open /presentation and verify the preview iframe loads the Analog blog routes without CORS, preview-secret, or Presentation lifecycle errors.
• Confirm pnpm blog:setup, pnpm blog:dev, and pnpm blog:typegen remain the documented local path for new contributors.
• Roll back by reverting this PR if builds, schema validation, or Presentation preview validation fail after merge.

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