Add @opentelemetry/sdk-trace-base to docs devDependencies

The documentation build was failing because Twoslash code examples in
docs/manual/opentelemetry.md import from @opentelemetry/sdk-trace-base,
but this package was not listed in docs/package.json devDependencies.

Since packages/fedify also depends on this package, moved the version
to pnpm catalog for consistency and used catalog reference in both
packages.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>