Fix critical build errors and remove duplicate JSX routes #4674

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Merge branch 'main' into claude/fix-dominat8-404-error-ukbBD

fix: unblock CI builds and PRs in GitHub Actions

fix: remove legacy pages/ directories and migrate dxl-auth-check to App Router

Add ALLOW_PROTECTED_PATHS to authorize protected path changes

chore: add tsconfig.tsbuildinfo to gitignore

feat: ship 4-track product expansion — scaffold engine, app builder, intelligence, stickiness

fix: move param() before Set-StrictMode in protected-paths.ps1

feat: upgrade home page, pricing, templates, sitemap, and 404 page

chore: add PLAN.md and updated package-lock.json

fix: resolve all build-breaking errors — site can now deploy