#19063: CI/macOS: disable Vitest vmForks for TS tests to stop mock-state leakage flakes

## Summary This PR stabilizes the macOS TypeScript CI job by disabling Vitest `vmForks` for that job only. The macOS workflow currently runs: - `pnpm test` On CI, `scripts/test-parallel.mjs` enables `vmForks` by default. In that mode, we observed cross-file mock/module-state contamination leading to order-dependent false negatives (for example, `vi.fn()` call-count assertions unexpectedly at 0, missing mocked exports, and unrelated suites failing together). ## Root Cause The failures are caused by test-runner isolation behavior under `CI + vmForks`, not by the feature code in the failing PRs. Evidence from reproduction: - `CI=true pnpm test` -> reproducible random mock-related failures across unrelated suites. - `CI=true pnpm test -- src/web/inbound/send-api.test.ts src/process/supervisor/adapters/child.test.ts` -> both pass in isolation. - `CI=true OPENCLAW_TEST_VM_FORKS=0 pnpm test` -> full suite passes. ## Change In `.github/workflows/ci.yml`, for `macos` -> `TS tests (macOS)`: - Add `OPENCLAW_TEST_VM_FORKS: "0"` This keeps the fix narrowly scoped to the flaky job while preserving existing behavior elsewhere. ## Why This Scope - The observed blocker is the macOS CI TS job. - This patch avoids broad test runner policy changes and minimizes risk. - We can evaluate broader `vmForks` policy separately if needed. ## Validation - Reproduced CI-only flake locally with `CI=true`. - Verified deterministic pass with `OPENCLAW_TEST_VM_FORKS=0`. - Confirmed targeted failing tests pass in isolation. <!-- greptile_comment --> <h3>Greptile Summary</h3> Disabled Vitest `vmForks` for macOS CI to prevent cross-file mock-state contamination causing flaky test failures. The change sets `OPENCLAW_TEST_VM_FORKS: "0"` which `scripts/test-parallel.mjs` respects to fall back to standard forks-based test execution. This is a targeted fix for observed CI-only flakes without affecting other platforms or local development. <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk - Single-line config change that disables a specific test runner feature for one CI job. The environment variable is explicitly supported by the test infrastructure (test-parallel.mjs:55-57), fallback behavior is well-tested, and the scope is narrowly limited to macOS CI without affecting other platforms or local development - No files require special attention _{Last reviewed commit: 4a46bcd} <!-- greptile_other_comments_section --> <!-- /greptile_comment -->