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

packages/core-runner-protocol/turbo.json

@@ -0,0 +1,4 @@
+{
+  "extends": ["//"],
+  "tags": ["core"]
+}