FN-6610: harden engine test isolation recovery
Harden shared test isolation seams so engine tests survive mid-run cleanup.
- Recreate owned worker roots, HOME directories, and cwd before child-process launches.
- Add regression coverage for tmpdir redirect, HOME, cwd, SQLite, and git config recovery.
- Revalidate worktree database scratch directories before direct SQLite opens and document the rescue pattern.
Files changed:
docs/testing.md | 2 +
packages/core/src/__test-utils__/vitest-setup.ts | 92 ++++++++++++++++++----
.../__tests__/vitest-setup-tmp-redirect.test.ts | 33 ++++++++
.../src/__tests__/executor-step-session.test.ts | 6 +-
.../src/__tests__/worktree-db-hydrate.test.ts | 22 +++++-
5 files changed, 135 insertions(+), 20 deletions(-)
Fusion-Task-Id: FN-6610
Fusion-Task-Lineage: 18233ee2-1dfe-4b0d-bd12-e4f5b7f9cc29