docs: correct stale no-op comments in node test setup

setup/node.ts installs the no-instrumentation guard (vi.mock against
real Sentry/OTel SDK init) via its import — it was never a no-op. Fix
the same lie in core-typescript's jsdom base-config test comments and
test title. (S2)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

packages/core-testing/src/setup/node.ts

@@ -1,5 +1,6 @@
 import "./no-instrumentation";
 
-// Reserved for future global node-env setup. Currently a no-op so that
-// vitest configs may reference @repo/core-testing/setup/node uniformly.
+// Applies the no-instrumentation guard (vi.mock against real Sentry/OTel SDK
+// init) via the import above; otherwise reserved for future global node-env
+// setup so vitest configs may reference @repo/core-testing/setup/node uniformly.
 export {};