docs(phase-03): update VALIDATION.md — Nyquist-compliant (partial)

15 automated tests green, 4 manual-only (PostgreSQL/migration infra).
Added 4 previously unlisted passing tests to task map (D-15, D-16, D-09×2).
Audit trail appended. Status: nyquist_compliant: true, status: partial.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/phases/03-document-migration-multi-user-isolation/03-VALIDATION.md

@@ -1,10 +1,11 @@
 ---
 phase: 3
 slug: document-migration-multi-user-isolation
-status: draft
-nyquist_compliant: false
-wave_0_complete: false
+status: partial
+nyquist_compliant: true
+wave_0_complete: true
 created: 2026-05-23
+audited: 2026-05-31
 ---
 
 # Phase 3 — Validation Strategy
@@ -38,29 +39,65 @@ created: 2026-05-23
 
 | Task ID | Plan | Wave | Requirement | Threat Ref | Secure Behavior | Test Type | Automated Command | File Exists | Status |
 |---------|------|------|-------------|------------|-----------------|-----------|-------------------|-------------|--------|
-| Migration null-user cleanup | 01 | 1 | D-02 | SEC-04 | Null-user docs deleted before NOT NULL constraint | integration | `pytest tests/test_alembic.py::test_migration_0003 -x` | ❌ W0 | ⬜ pending |
-| Quota reconciliation | 01 | 1 | D-03 | STORE-03 | used_bytes matches SUM(size_bytes) post-migration | integration | `pytest tests/test_alembic.py::test_migration_0003 -x` | ❌ W0 | ⬜ pending |
-| Atomic quota enforce | 02 | 2 | STORE-03 | STORE-03 | No double-spend on concurrent uploads | unit+integration | `pytest tests/test_quota.py -x` | ❌ W0 | ⬜ pending |
-| Concurrent quota race | 02 | 2 | STORE-03 (SC2) | STORE-03 | Two concurrent uploads at limit → exactly one 413 | integration | `pytest tests/test_quota.py::test_concurrent_quota_race -x` | ❌ W0 | ⬜ pending |
-| Quota exceeded response | 02 | 2 | STORE-05 | STORE-05 | 413 with {used_bytes, limit_bytes, rejected_bytes} | unit | `pytest tests/test_quota.py::test_quota_exceeded_response -x` | ❌ W0 | ⬜ pending |
-| Atomic quota decrement | 02 | 2 | STORE-06 | STORE-06 | Delete decrements quota atomically | unit | `pytest tests/test_quota.py::test_delete_decrements_quota -x` | ❌ W0 | ⬜ pending |
-| Upload-url endpoint | 02 | 2 | D-05 | SEC-04 | Creates pending Document row + returns presigned URL | unit | `pytest tests/test_documents.py::test_upload_url_endpoint -x` | ❌ W0 | ⬜ pending |
-| Confirm endpoint | 02 | 2 | D-05 | STORE-03 | stat_object size used, status=uploaded set | unit | `pytest tests/test_documents.py::test_confirm_endpoint -x` | ❌ W0 | ⬜ pending |
-| Quota bar endpoint | 02 | 2 | STORE-04 | — | GET /api/me/quota returns {used_bytes, limit_bytes} | unit | `pytest tests/test_documents.py::test_get_quota -x` | ❌ W0 | ⬜ pending |
-| Cross-user access | 03 | 3 | SEC-04 | SEC-04 | Cross-user document access returns 404 | unit | `pytest tests/test_documents.py::test_cross_user_access_404 -x` | ❌ W0 | ⬜ pending |
-| Admin 403 on documents | 03 | 3 | SEC-04 (SC4) | SEC-04 | Admin JWT on /api/documents/* returns 403 | unit | `pytest tests/test_documents.py::test_admin_cannot_access_documents -x` | ❌ W0 | ⬜ pending |
-| Topic namespace isolation | 03 | 3 | DOC-04 | — | Topic list = system topics + own topics only | unit | `pytest tests/test_topics.py::test_topic_namespace -x` | ❌ W0 | ⬜ pending |
-| Per-user AI provider | 04 | 4 | DOC-03/DOC-05 | — | Classifier uses user's assigned provider not global | unit | `pytest tests/test_classifier.py::test_per_user_provider -x` | ❌ W0 | ⬜ pending |
-| Celery task provider lookup | 04 | 4 | DOC-05 | — | Celery task resolves provider from document owner's DB | unit | `pytest tests/test_classifier.py::test_celery_task_uses_user_provider -x` | ❌ W0 | ⬜ pending |
-| Settings endpoint removed | 04 | 4 | D-12 | — | /api/settings returns 404 | unit | `pytest tests/test_settings.py::test_settings_endpoint_removed -x` | ❌ W0 | ⬜ pending |
+| Atomic quota enforce | 02 | 2 | STORE-03 | STORE-03 | No double-spend on concurrent uploads | unit+integration | `pytest tests/test_quota.py::test_quota_increment_atomic -x` | ✅ | ✅ green |
+| Quota exceeded response | 02 | 2 | STORE-05 | STORE-05 | 413 with {used_bytes, limit_bytes, rejected_bytes} | unit | `pytest tests/test_quota.py::test_quota_exceeded_response -x` | ✅ | ✅ green |
+| Upload-url endpoint | 02 | 2 | D-05 | SEC-04 | Creates pending Document row + returns presigned URL | unit | `pytest tests/test_documents.py::test_upload_url_endpoint -x` | ✅ | ✅ green |
+| Confirm endpoint | 02 | 2 | D-05 | STORE-03 | stat_object size used, status=uploaded set | unit | `pytest tests/test_documents.py::test_confirm_endpoint -x` | ✅ | ✅ green |
+| Quota bar endpoint | 02 | 2 | STORE-04 | — | GET /api/me/quota returns {used_bytes, limit_bytes} | unit | `pytest tests/test_documents.py::test_get_quota -x` | ✅ | ✅ green |
+| Cross-user access | 03 | 3 | SEC-04 | SEC-04 | Cross-user document access returns 404 | unit | `pytest tests/test_documents.py::test_cross_user_access_404 -x` | ✅ | ✅ green |
+| Admin 403 on documents | 03 | 3 | SEC-04 (SC4) | SEC-04 | Admin JWT on /api/documents/* returns 403 | unit | `pytest tests/test_documents.py::test_admin_cannot_access_documents -x` | ✅ | ✅ green |
+| Topic namespace isolation | 03 | 3 | DOC-04 | — | Topic list = system topics + own topics only | unit | `pytest tests/test_topics.py::test_topic_namespace -x` | ✅ | ✅ green |
+| Per-user AI provider | 04 | 4 | DOC-03/DOC-05 | — | Classifier uses user's assigned provider not global | unit | `pytest tests/test_classifier.py::test_per_user_provider -x` | ✅ | ✅ green |
+| Celery task provider lookup | 04 | 4 | DOC-05 | — | Celery task resolves provider from document owner's DB | unit | `pytest tests/test_classifier.py::test_celery_task_uses_user_provider -x` | ✅ | ✅ green |
+| Settings endpoint removed | 04 | 4 | D-12 | — | /api/settings returns 404 | unit | `pytest tests/test_settings.py::test_settings_endpoint_removed -x` | ✅ | ✅ green |
+| Default provider fallback | 04 | 4 | D-15 | — | Classifier falls back to app_settings defaults when user has no provider | unit | `pytest tests/test_classifier.py::test_default_provider_fallback -x` | ✅ | ✅ green |
+| Documents require auth | 02 | 2 | D-16 | SEC-04 | Unauthenticated requests to /api/documents/* return 401 | unit | `pytest tests/test_documents.py::test_documents_require_auth -x` | ✅ | ✅ green |
+| Admin create system topic | 03 | 3 | D-09 | — | Admin can create is_system=true topics | unit | `pytest tests/test_topics.py::test_admin_create_system_topic -x` | ✅ | ✅ green |
+| User cannot create system topic | 03 | 3 | D-09 | — | Regular user POST with is_system=true returns 403 | unit | `pytest tests/test_topics.py::test_regular_user_cannot_create_system_topic -x` | ✅ | ✅ green |
 
 *Status: ⬜ pending · ✅ green · ❌ red · ⚠️ flaky*
 
 ---
 
-## Wave 0 Requirements
+## Manual-Only Tasks
 
-- [ ] `backend/tests/test_quota.py` — stubs for STORE-03, STORE-05, STORE-06, concurrent race
-- [ ] `backend/tests/test_alembic.py` — stub for migration 0003 test
-- [ ] `backend/tests/test_classifier.py` — stubs for DOC-03, DOC-05 per-user provider
-- [ ] `backend/tests/conftest.py` — `auth_user` fixture (authenticated user with quota row), `admin_user` fixture, MinIO mock fixtures for `presigned_put_object` and `stat_object`
+> These tasks require infrastructure not available in the unit test environment.
+> They must be verified manually before phase sign-off.
+
+| Task ID | Plan | Requirement | Why Manual | Verification Step |
+|---------|------|-------------|------------|-------------------|
+| Migration null-user cleanup | 01 | D-02 | Alembic upgrade requires a real PostgreSQL instance + migration scripts | `INTEGRATION=1 pytest tests/test_alembic.py::test_migration_0003 -x` against real DB |
+| Quota reconciliation | 01 | D-03 | Same migration test; verifies used_bytes matches SUM(size_bytes) post-migration | `INTEGRATION=1 pytest tests/test_alembic.py::test_migration_0003 -x` against real DB |
+| Concurrent quota race | 02 | STORE-03 SC2 | PostgreSQL row-level locking required; SQLite cannot emulate concurrent atomic UPDATE | `INTEGRATION=1 pytest tests/test_quota.py::test_concurrent_quota_race -x` against PostgreSQL |
+| Atomic quota decrement | 02 | STORE-06 | SQLite UUID format mismatch in GREATEST() WHERE clause; real PostgreSQL required | `INTEGRATION=1 pytest tests/test_quota.py::test_delete_decrements_quota -x` against PostgreSQL |
+
+---
+
+## Wave 0 Status
+
+- [x] `backend/tests/test_quota.py` — STORE-03, STORE-05, STORE-06, concurrent race
+- [x] `backend/tests/test_alembic.py` — migration 0003 test (manual-only)
+- [x] `backend/tests/test_classifier.py` — DOC-03, DOC-05, D-15 per-user provider
+- [x] `backend/tests/test_documents.py` — D-05, D-16, STORE-04, SEC-04
+- [x] `backend/tests/test_topics.py` — DOC-04, D-09
+- [x] `backend/tests/test_settings.py` — D-12
+- [x] `backend/tests/conftest.py` — auth_user, admin_user, MinIO mock fixtures
+
+---
+
+## Validation Audit 2026-05-31
+
+| Metric | Count |
+|--------|-------|
+| Tasks in map | 19 |
+| Automated (green) | 15 |
+| Manual-only | 4 |
+| Gaps found | 10 |
+| Resolved (xfail removed) | 2 |
+| Added to task map | 4 |
+| Escalated to manual-only | 4 |
+
+**Changes made:**
+- Removed stale `xfail` markers from `test_quota_increment_atomic` and `test_quota_exceeded_response` (both XPASS → now clean PASSED)
+- Added 4 unlisted-but-passing tests to task map: `test_default_provider_fallback` (D-15), `test_documents_require_auth` (D-16), `test_admin_create_system_topic` (D-09), `test_regular_user_cannot_create_system_topic` (D-09)
+- Moved 4 infrastructure-blocked tasks to Manual-Only: migration null-user cleanup, quota reconciliation, concurrent quota race, atomic quota decrement