Routing pattern consistency

Next.js routing resolution between app/ and pages/ follows non-obvious precedence rules: App Router wins for matching segments, but Pages Router catches everything App Router does not claim. Deploying a half-migrated app can change which route renders simply because someone added or removed a file, with no local indication. SEO metadata, layouts, and data-fetching conventions differ completely between the two routers, producing broken canonical URLs and duplicated or missing OG tags.

Finish the migration to App Router. Enumerate what remains:

find pages -type f -name "*.tsx" | grep -vE '_app|_document|_error|api/'

Move each remaining page into app/ (e.g., pages/about.tsx becomes app/about/page.tsx), port getServerSideProps to server components or route handlers, then delete the old file. Keep pages/api/ until those endpoints are migrated to app/api/ route handlers. Redeploy and verify every URL resolves through the expected router.