docs(ai): handoff after CI parallelization + final test fix

Updates HANDOFF.md, CURRENT_TASK.md, and SESSION_LOG.md to reflect:
- PR #150 now contains the AI-provider test mock + caching + maxfail.
  Backend CI should be fully green for the first time in months.
- PR #151 stacked on #150: pytest-xdist with per-worker DBs. Local
  verification: 22m 27s → 4m 28s (5× speedup), 1076 passed both runs.
- DoD is now: merge #150, then #151, then add CI / backend
  (pull_request) to required status checks on main.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

.ai/CURRENT_TASK.md

@@ -1,22 +1,22 @@
 # CURRENT_TASK.md
 
-**Task:** Restore a fully green CI gate on `main` and lock it via branch protection so future merges can't introduce silent rot.
+**Task:** Land two stacked CI PRs and lock the backend gate on `main`.
 
 **Status:** in-progress
 
 **Definition of Done:**
 - [ ] PR #150 (`fix/ci-workflow-config`) merged. Both `CI / backend (pull_request)` and `CI / frontend (pull_request)` show success on the merge commit.
+- [ ] PR #151 (`fix/ci-pytest-xdist`) merged. Backend CI on the merge commit completes in <6 min (was ~22 min serial).
 - [ ] `CI / backend (pull_request)` added to required status checks on `main` in Gitea branch protection (frontend is already required).
-- [ ] The 54 real backend test failures (left after #149's infra cleanup) categorized and fixed in a follow-up PR. Target: 0 failures, 0 errors on a `pytest` run inside `resolutionflow_backend`.
-- [ ] `npm run lint` stays at 0 errors after the cleanup PR (already at 0 on main).
-- [ ] Append a SESSION_LOG.md entry summarizing what shipped.
+- [ ] Optional: `CI / e2e (pull_request)` confirmed clean and added to required checks.
 
 **Assumptions:**
-- The 54 failures fall into a small number of root-cause categories (likely 3–5: fixture-scoping leaks, DB cleanup ordering, account_id propagation in test seed paths). Verify before assuming.
-- The pytest-asyncio 0.24 + pytest 8.4 toolchain bumped in #149 is the right baseline; do not revert.
-- `DATABASE_TEST_URL` is the only DB URL conftest will honor; do not weaken the safety guard added in `dab740d`.
+- The 8-core homelab Gitea Actions runner can support `-n auto` (8 xdist workers). If memory pressure shows up in CI, drop to `-n 4`.
+- pytest-cov's xdist support continues to handle the coverage merge and `--cov-fail-under=50` check correctly.
+- The per-worker DB creation in `conftest.py` is idempotent and racing workers on first import won't all try to CREATE DATABASE simultaneously — postgres serializes that, but if it surfaces issues, wrap with an advisory lock.
 
 **Out of scope:**
-- New feature work on FlowPilot (Phase 10+) or PSA — keep this branch focused on CI debt.
-- Frontend lint warnings (23 remain after #149; they're missing-deps in useEffect, opt-in cleanup later).
-- RLS test suite (`test_rls_isolation.py`) — gated behind `RUN_RLS_TESTS=1` and not in the default CI run.
+- Frontend lint warnings (23 remain after #149).
+- The 23 react-hooks/exhaustive-deps warnings.
+- RLS test suite (gated behind `RUN_RLS_TESTS=1`; not in default CI).
+- Per-test transactional rollback (would shave another 30-40% off backend time but is a much bigger refactor — capture in TODO if interested).