TypeScript emits an informational diagnostic when source files span
multiple top-level dirs (src/ + tests/) without explicit rootDir.
Setting rootDir="." satisfies the recommendation and matches the
include pattern. Updates blog, auth, marketing-pages — and Plan 4
doc so navigation (still pending) starts correct.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>