Move better-sqlite3 to optionalDependencies so npm install doesn't
fail on platforms without native build tools. Add it to
serverExternalPackages so Next.js doesn't try to bundle the native
addon into webpack chunks.
Fixes#243
Cherry-picked from decolua/9router PR #183.
Note: open-sse changes included but need further review due to extensive modifications.
Co-authored-by: Cursor <cursoragent@cursor.com>
Ibrahim Ryan