[CLAUDE] Docs+Skill: chốt Session 16 wrap-up — drastic refactor flat workflow (Chunk D)

Session 16 (2026-05-08) docs/skill/memory wrap-up:

STATUS.md:
- Last updated Session 16 (2 commit Chunk A+B)
- Phase summary count (20→21 mig, 96→77 test, 57→55 bảng)
- Recently Done row Session 16 chi tiết (drastic refactor hoàn tất)
- Phase enum simplified semantic post-Mig 21

HANDOFF.md:
- TL;DR Session 16 prepend với 2 chunk + Chunk C SKIP rationale
- Per-chunk implementation chi tiết (Domain + Mig 21 + Service + Tests
  + FE Designer)
- 8 cảnh báo Session 17+: UAT live test / old data migration / Sample
  seed / Budget N-stage / schema-diagram / skill refresh / tests flat /
  Hard blockers Ops

migration-todos.md: Phase 9 + Session 16 block 2 chunk done + 7 defer task

Session log NEW `2026-05-08-0500-drastic-refactor-flat-workflow.md`:
- Bối cảnh resume từ S15 defer
- Spec implementation (Phase enum, state machine, schema Mig 21)
- Per-chunk Chunk A + Chunk B detail
- Chunk C skip rationale
- Memory `feedback_drastic_refactor_scope` validation:
  scope estimate 30% accurate (3h actual vs 10h conservative)
- Plan organization sau S16

Skill ef-core-migration:
- description + heading: 20→21 migration
- + Mig 21 row "RefactorWorkflowToFlatModel" với detail (4 ALTER + 2
  ALTER + DROP TABLE × 2 + DROP COLUMN × 2 + restore simple unique × 2)
- Total 57→55 bảng (-2 InnerStep tables)
- Tests: 96→77 (drop 19 legacy)

CLAUDE.md root:
- Migration count 20→21
- DB tables 57→55
- Workflow flat description thay N-stage description

docs/rules.md §7: 96→77 test (Mig 21 simplified)

Memory `project_solution_erp.md`:
- Add "Tổng sau session 16" block với drastic refactor details

🎉 Session 16 wrap-up. Cumulative since session start (S15 wrap-up
`38d10b7`): 4 commit (S15 wrap-up was final S15) + 3 commit Session 16
(A `dbb0089` + B `88a5be1` + D current).

Defer Session 17+ priority:
1. UAT live test workflow flat (3 phòng × N cấp realistic)
2. Old PE/HĐ legacy phase data migration
3. Sample data seed (Task 2 carry-over)
4. Hard blockers Ops

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

docs/changelog/migration-todos.md

@@ -157,6 +157,25 @@ Session log: `2026-04-28-chot-session-4-budget.md`.
 
 ## 📝 Phase 9 — UAT + Ops + carry over (Session 6+ active)
 
+### ✅ Session 16 done (2026-05-08) — DRASTIC REFACTOR flat workflow Phòng × Cấp (Mig 21, 2 commit Chunk A+B)
+
+User chốt drastic refactor: bỏ phase enum hoàn toàn, dùng ChoDuyet=10 đơn nhất + currentStepIndex tracking. Workflow flat list (Phòng × Cấp × Approvers). Pin WorkflowDefinitionId. Per memory `feedback_drastic_refactor_scope.md`: dedicated session + conservative buffer.
+
+- [x] **Chunk A (`dbb0089`)** All BE — Domain enum simplify (ChoDuyet=10, legacy 2-6+98 deprecated giữ data cũ) + WorkflowStep +DepartmentId/PositionLevel + PE/Contract +CurrentWorkflowStepIndex/RejectedAtStepIndex + drop InnerStep entity/nav (PE+Contract) + drop *DeptApproval.InnerStepId + EF Configurations restore simple unique non-filtered + DbContext drop DbSets. **Migration 21** `RefactorWorkflowToFlatModel` GỘP (4 ALTER cols PE/Contract + 2 ALTER WorkflowStep + DROP TABLE × 2 + DROP COLUMN InnerStepId × 2 + restore simple unique × 2). Service rewrite TransitionAsync flat logic (Drafter trình → init idx=0, advance idx per approve, last step → DaDuyet/DaPhatHanh, Trả lại save RejectedAtStepIndex, Resume jump-back, Match approver Dept+PositionLevel OR Approvers Role/User). App CQRS DTOs simplified. Tests DROP PeNStageApprovalTests + ContractNStageApprovalTests + PeTwoStageApprovalTests (19 test legacy). UPDATE PeWorkflowAdminTests signature. **96 → 77 test pass**. 3-file rule Mig 21 commit đủ.
+
+- [x] **Chunk B (`88a5be1`)** FE Designer — PeWorkflowsPage + WorkflowsPage rewrite (~210 LOC each): drop InnerStep types + PHASE_OPTIONS, auto-assign ChoDuyet=10, step UI Tên + Phòng Select + Cấp Select + SLA + Approvers Role/User optional fallback, drop InnerSteps sub-section, DefinitionCard view badge Phòng/Cấp. types/purchaseEvaluation.ts (fe-admin + fe-user mirror) + ChoDuyet=10 enum + label "Đang duyệt" + color amber. KHÔNG đụng PeWorkflowPanel (Chunk C SKIP — existing UI compatible).
+
+- [⊘] **Chunk C (FE PeWorkflowPanel + workflow timeline) SKIP** — existing UI dùng `workflow.nextPhases` BE-driven, 3-button Trả lại/Từ chối Session 14 reuse với target=DangSoanThao/TuChoi pattern. KHÔNG cần đụng.
+
+**Defer Session 17+:**
+- [ ] UAT live test workflow flat (3 phòng × N cấp setup)
+- [ ] Old PE/HĐ data migration (pinned legacy workflow phase 2-6 stuck) — admin manual transition hoặc data migration script
+- [ ] Sample data seed N-stage (block DesignTime vs Runtime DB)
+- [ ] Budget N-stage (cần versioned WF migration)
+- [ ] schema-diagram §17-21 update (cron audit 2026-06-01)
+- [ ] Skill ef-core-migration + contract-workflow refresh (cron audit)
+- [ ] Tests cho flat workflow flow (làm khi UAT bug)
+
 ### ✅ Session 15 done (2026-05-07) — Tooltip diagnose "Lưu & Gửi Duyệt" + drastic refactor flat workflow DEFER (1 commit)
 
 User UAT live báo button "Lưu & Gửi Duyệt" KHÔNG hoạt động + suy đoán "trùng ID". Diagnose: silent disabled khi `nextPhases` không có forward phase. Add tooltip + dialog warning. "Trùng ID" KHÔNG phải bug FE.