[CLAUDE] FE-Admin+Docs: PE workflow N-stage Designer + UsersPage cấp + Docs (Chunk F)

FE Admin:
- types/users.ts: User +positionLevel field + PositionLevel const +
  PositionLevelLabel/Short maps (NV/PP/TP).
- PeWorkflowsPage.tsx Designer extend: InnerStepDto + EditInnerStep types,
  copyFromDefinition include, departmentsList query, sub-section "Cấp duyệt
  nhỏ trong phòng" per step card với drag-list { Phòng × Cấp + required }
  + button "+ Thêm cấp duyệt" emerald + payload include (Order asc).
  Empty state hint fallback 2-cấp legacy.
- UsersPage.tsx: column "Cấp" badge NV/PP/TP emerald (— nếu null) +
  action button cycle null→1→2→3→null call PATCH /users/{id}/position-level.

KHÔNG đụng fe-user — admin-only feature (PeWorkflowsPage + UsersPage ở
fe-admin only).

Docs:
- STATUS.md Last updated + Phase summary count (17→19 mig, 83→89 test,
  55→56 bảng) + 1 row Recently Done Session 12 (KEEP narrative cũ).
- HANDOFF.md TL;DR Session 12 prepend + 8 cảnh báo Session 13+ + giữ
  Session phase 2 narrative.
- migration-todos.md Phase 9 + Session 12 block 6 chunk + 5 defer task.
- session log NEW `2026-05-07-2300-n-stage-workflow.md` đầy đủ rationale
  + per-chunk + bug log + plan hierarchy.

Defer cron audit 2026-06-01: schema-diagram §15 Mig 18 + §16 Mig 19,
skill ef-core-migration Mig 18+19 row, skill contract-workflow N-stage
cross-ref section.

Verify:
- npm run build fe-admin pass (✓ built, 0 TS error)
- dotnet test 89 pass (no regression)
- dotnet build 0 error

🎉 SESSION 12 COMPLETE: N-stage workflow approval Phòng × PositionLevel
PE-only. Backward compat 100% với 2-stage Mig 16. 6 commit per-chunk
A→F. Total 89 test pass.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

docs/changelog/migration-todos.md

@@ -157,6 +157,26 @@ Session log: `2026-04-28-chot-session-4-budget.md`.
 
 ## 📝 Phase 9 — UAT + Ops + carry over (Session 6+ active)
 
+### ✅ Session 12 done (2026-05-07) — N-stage workflow approval (Mig 18+19, 6 commit per-chunk, PE-only)
+
+User yêu cầu: workflow level cha (= phase) cấu hình được level con (Phòng × Cấp NV/PP/TP) sequential, mỗi cấp = 1 inner step duyệt riêng, có bypass cùng dept. 6 spec defaults chốt + 6 chunk per-commit.
+
+- [x] **Chunk A (`13ab533`)** Domain + Migration 18 `AddPeWorkflowInnerStepsAndPositionLevel` — enum PositionLevel (NV/PP/TP), entity PurchaseEvaluationWorkflowStepInnerStep + nav, User.PositionLevel int? + PEDeptApproval.InnerStepId Guid?. EF config FK Cascade Step / Restrict Dept+InnerStep. 3-file rule.
+- [x] **Chunk B (`0e56bd0`)** Application CQRS DTO — PeWorkflowStepInnerStepDto + extend PeWorkflowStepDto + CreatePeWorkflowStepInnerStepInput (default null backward compat) + Validator child rules + Handler atomic batch insert + UserDto +PositionLevel + SetUserPositionLevelCommand mirror SetBypassReview pattern.
+- [x] **Chunk C (`0c62e24`)** Service N-stage logic + **Migration 19** `AlterPeDeptApprovalsUniqueFilteredForInnerSteps` (filtered unique legacy `WHERE InnerStepId IS NULL` + new N-stage `WHERE InnerStepId IS NOT NULL`). PurchaseEvaluationWorkflowService refactor — load InnerSteps eager, reject clear N-stage rows tại fromPhase, dept block split hasInnerSteps→N-stage / else→legacy 2-stage. N-stage: match firstPending (Order asc IsRequired) same dept + (exact level OR canBypass + level≥), exact upsert 1 row InnerStepId, bypass batch upsert NV+PP+TP cùng dept ≤ actor (audit IsBypassed cho cấp dưới), recheck stillPending → BLOCK + log "duyệt cấp X (còn Y pending)".
+- [x] **Chunk D (`3d76c6b`)** Tests N-stage 6 test mới (FirstInner_NV_blocks / All_3_levels_sequential_pass / TP_bypass_skips_lower / Wrong_dept_403 / Reject_clears_rows / Legacy_fallback_no_inner) + IdentityFixture extend `+positionLevel` + helper SeedWorkflowDefinitionAsync 2 step adjacent. **83→89 test pass**.
+- [x] **Chunk E (`83ffabd`)** API `PATCH /users/{id}/position-level` mirror SetBypassReview + body `{positionLevel:int?}` + Authorize Users.Update.
+- [x] **Chunk F (current)** FE-Admin types/users.ts + positionLevel field + PositionLevel const + Label/Short maps. PeWorkflowsPage Designer extend InnerStep DTO + EditInnerStep type + sub-section "Cấp duyệt nhỏ trong phòng" drag-list { Phòng × Cấp + required } + button "+ Thêm cấp duyệt" emerald + departmentsList query + payload include. UsersPage column "Cấp" badge NV/PP/TP emerald + action button cycle null→1→2→3→null. KHÔNG đụng fe-user (admin-only).
+
+**Backward compat 100%:** workflow no InnerSteps configured → service fallback legacy 2-stage Mig 16. Data legacy rows InnerStepId=null vẫn enforce unique cũ qua filtered index.
+
+**Defer Session 13+:**
+- [ ] Mirror Contract + Budget N-stage (sau khi UAT PE 2-3 tuần ổn). Pattern lặp lại Domain entity + Service logic + Tests reusable từ PE.
+- [ ] Seed/migrate User.PositionLevel cho 30 demo user (hiện chỉ admin set qua UsersPage cycle).
+- [ ] schema-diagram.md §15 Mig 18 + §16 Mig 19 update (defer cron audit 2026-06-01 — small drift).
+- [ ] Skill ef-core-migration row Mig 18+19 (defer cron audit).
+- [ ] Skill contract-workflow N-stage cross-ref section (defer cron audit).
+
 ### ✅ Session phase 2 done (2026-05-08 00:30) — B12-B14 PE detail polish iterate (3 commit FE-only)
 
 User UAT iteration tiếp sau wrap-up `6e7a6db`. Áp rule strict verify khi rename/remove (lesson hotfix CI).