* test: reduce low-memory Vitest pressure
Reuse the bundled config baseline inside doc-baseline tests, keep that hotspot out of the shared unit-fast lane, and make OPENCLAW_TEST_PROFILE=low default to process forks instead of vmForks.
* test: keep low-profile vmForks in CI
Scope the low-profile forks fallback to local runs so the existing CI contracts lane keeps its current pool behavior.