feat(core-runner-protocol): scaffold protocol package

Hand-scaffolded from the packages/core-events shape: the core-package
turbo generator only covers its eight pre-curated snapshot names
(analytics, audit, consent, dsr, events, realtime, trpc, ui) and
rejects 'runner-protocol' at the name prompt. Flagged in the package
AGENTS.md as a future generator snapshot candidate.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016j8z4VHjedXDTjEDNg7qHK

apps/web-next/next.config.mjs

@@ -12,6 +12,7 @@ const nextConfig = {
     "@repo/core-dsr",
     "@repo/core-events",
     "@repo/core-realtime",
+    "@repo/core-runner-protocol",
     "@repo/core-shared",
     "@repo/core-trpc",
     "@repo/core-ui",