# Implementer-Backend Agent — Persistent Memory

> **Persistent diary cross-session.** Auto-injected first ~200 lines at spawn (L1 HOT).
> Update BEFORE every stop. Tiered Memory v1: L1 HOT soft-cap ~30KB · L2 `archive/` on-demand · L3 RAG `search_memory` just-in-time. Keep entry ≤ 1.5K chars (gotcha #53).
> Full verbatim history pre-S40 → git `d2f52ba` + `archive/2026-05-q1..q4.md` + `archive/2026-06.md`. 🗺️ **Lookup map (Harness-9 S70): `archive/_INDEX.md`** — 1 dòng/bản-ghi + con-trỏ substring (sha-keyed, Ctrl-F fallback); đọc verbatim + `2026-0{5,6}.gist.md` (nén 4-field) theo nhu cầu.
> **Renamed S39:** implementer → implementer-backend (.NET half). FE patterns → `implementer-frontend` MEMORY. Test patterns → `test-specialist` MEMORY.

---

## 🎯 Role baseline

WRITE specialist .NET backend SOLUTION_ERP (`Domain+Application+Infrastructure+Api`). Case 1+2+3+5 only. Tools: Read, Edit, Write, Bash, Skill, Grep, Glob + 5 RAG MCP. Skills: `ef-core-migration` + `permission-matrix` + `contract-workflow` + `form-engine`. Output: commits + verify report.

## 🚫 Split boundary (S39) + auto-refuse
- ✅ MINE: `src/Backend/SolutionErp.{Domain,Application,Infrastructure,Api}/**`
- ❌ NOT: `fe-*/**` → `implementer-frontend` · `tests/**` → `test-specialist` · schema/UX/architecture decision → em main
- **REFUSE if ANY:** 1 schema design (FK/nullable/discriminator) · 2 UX flow · 3 cross-stack >2 layer · 4 bug fix reasoning chain · 5 integration multi-component · 6 <30min trivial · 7 first-time no precedent · 8 spec ambiguity >20%

---

## 📋 BE Patterns proven (apply confidently)

### Pattern 1: Per-chunk discipline A-E
A Domain+Mig (3-file) · B Application CQRS (Command/Query/Validator) · C Service (workflow logic) · D Api Controller · E commit. Build+test pass mỗi chunk. Commit `[CLAUDE] <scope>: Chunk X — ...` + Co-Authored-By Claude Opus 4.8 (1M context).

### Pattern 2: EF migration 3-file rule (gotcha #17 — BẮT BUỘC commit đủ)
`{TS}_{Name}.cs` + `.Designer.cs` + `ApplicationDbContextModelSnapshot.cs`. Path `src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/`.
```bash
dotnet ef migrations add <Name> --project src/Backend/SolutionErp.Infrastructure --startup-project src/Backend/SolutionErp.Api
# Apply Dev (runtime): --connection "Server=(localdb)\MSSQLLocalDB;Database=SolutionErp_Dev;Trusted_Connection=True;TrustServerCertificate=true"
# Apply Design (ef default): không cần --connection
```
Apply BOTH DB per `feedback_designtime_runtime_db`.

### Pattern 3: Audit reuse trước khi clone (`feedback_audit_reuse_before_clone`)
"Clone X→Y": grep discriminator (`ApplicableType`/`Type`/`Kind`) → check Service/Handler hardcode → check FE route dynamic → check menu key (BE const + FE menuKeys.ts thường thiếu) → default reuse 80%, chỉ thêm menu key + sample seed.

### Pattern 4: Service hook vs CRUD endpoint cho derived state (`feedback_service_hook_vs_endpoint`)
State X derived của action Y → UPSERT trong handler Y, KHÔNG endpoint /X riêng. VD `ApproveV2Async` UPSERT LevelOpinion qua match `ApproverUserId==actorUserId` (fallback first khi Admin override). 0 endpoint mới.

### Pattern 7: Per-NV admin opt-in flag (Mig 29/30/31)
`ApprovalWorkflowLevel` +1 `bool` DEFAULT 0 (opt-in). EF `HasDefaultValue(false)`. DTO extend. FE Designer checkbox inline. Scope role-context → table mapping (Approver→Level table carry ApproverUserId FK, Drafter→User table direct, `feedback_per_nv_permission_scope`). Reusable F5/F6.

### Pattern 8: Tách endpoint riêng cho narrow scope
1 action 2 scope theo role → tách endpoint (guard tự nhiên + audit). VD Drafter `UpdatePeDraft` (Section 1 rộng, phase Nháp/Trả lại) vs Approver `AdjustBudget` (Budget rows hẹp, phase Đang duyệt + per-NV flag). KHÔNG default expand Drafter scope cho Approver.

### Pattern 9: Defense-in-depth FE+BE guard pair
UI `disabled={!canX}` + BE helper `EnsureCanXAsync(id, userId)` throw 403 (NOT inline handler) — tránh forge qua DevTools. Bất kỳ action sensitive (approve/reject/adjust).

### Pattern 12-bis: Cross-module entity cookie-cutter mirror (S29 Plan B, proven 3×)
"Mirror entity X từ module A→B": 6 file MAX — (1) new entity `Domain/<Mod>/<Entity>.cs` rename FK+nav · (2) parent +nav collection · (3) IApplicationDbContext +DbSet · (4) ApplicationDbContext +`Set<X>()` · (5) new `<Entity>Configuration.cs` (separate file mirror PE, NOT inline) · (6) `dotnet ef migrations add` 3-file. AuditableEntity inherit. FK: parent Cascade + 3rd-party Restrict + User skip-nav (denorm `<Type>ByFullName`). Apply 2 DB. ⚠️ Catalog-mega variant (S35 HrmConfig): HRM entities KHÔNG có global `HasQueryFilter(!IsDeleted)` (vs Master) → list query MUST `.Where(!IsDeleted)` thủ công (verify `Grep HasQueryFilter` Configurations FIRST). Validator MaxLength MATCH EF config (verify source-of-truth, KHÔNG trust spec blind).

### Pattern 12-ter: N≤7 satellite CRUD scaffold same parent (S34, `feedback_within_module_n_satellite_scaffold`)
"N satellite cùng parent" → 1 mega file `<Parent>SatelliteFeatures.cs` N region cookie-cutter (Create verify parent `AnyAsync` → Update `FirstOrDefault !IsDeleted` → Delete soft `IsDeleted+DeletedAt+DeletedBy` ICurrentUser) + 1 Controller extend (3 verb × N). Endpoint verify `parentId==cmd.ParentId` BadRequest mismatch. Per-action policy override class-level Read.

### Patterns moved (split S39)
- **FE patterns** (5 mirror 2-app · 6 VND helpers · 13 read-only Designer · 14 Tailwind JIT palette · 15 rowSpan builder · **16-bis 4-place mirror**) → `implementer-frontend` MEMORY (seeded).
- **Test patterns** (10 reflection authz · 11 test infra helper · 12 InternalsVisibleTo) → `test-specialist` MEMORY (seeded).

---

## ⚠️ Anti-patterns (DO NOT)
1. ❌ Skip MEMORY · 2. ❌ `--no-verify` · 3. ❌ `git add -A`/`git add .` (specific files) · 4. ❌ Touch outside spec scope · 5. ❌ Push remote autonomous (em main pushes) · 6. ❌ Modify `SolutionErp.slnx` autonomous · 7. ❌ Lower bar match em main (Smart Friend) · 8. ❌ Proceed khi ambiguity >20% → REFUSE

---

## 🧠 SOLUTION_ERP BE conventions (S40)
- **BE .NET 10:** PascalCase entities + DTO records + command names. CQRS+MediatR+FluentValidation+AutoMapper. Repository qua `IApplicationDbContext`. `GlobalExceptionMiddleware` → ProblemDetails (NO try-catch controllers).
- **State S53:** 47 mig (last `FilterMasterCatalogUniqueIndexesByIsDeleted` Mig 47, index-only) · 93 SQL tables · ~224 endpoints · 203 test (58 Domain + 145 Infra, test-specialist owns). Phase 9 UAT skip per chunk (`feedback_uat_skip_verify`).
- **Build:** `dotnet build SolutionErp.slnx` clean 0 err. Commit `[CLAUDE] <scope>: <msg>` + Co-Authored-By Claude Opus 4.8 (1M context).
- **Pin (KHÔNG `*`/latest):** MediatR `12.4.1` (14 fail DI) · Swashbuckle `6.9.0` · Node CI `20.x` · LibreOffice `25.8.6` · @microsoft/signalr `8.0.7`.

---

## 📅 Recent activity (FIFO — older → archive/git)

- **2026-07-12 (S113 Supplier import v2 BE — spec `wf_e7896ca6` fable-clone-ensemble, owner anh Kiệt, Mig 64, D1/D2/D3 pre-chốt → ACCEPT Case 1+2; ⚠️ return-1 garbled #53 → coordinator SendMessage-resume, xong solo):** IsPublic publish-gate + dedup MST-primary. **Mig 64 `AddSupplierPublishState`** (Supplier +`bool IsPublic` NOT NULL default false + `Sql("UPDATE Suppliers SET IsPublic=1")` backfill 22 prod + DropIndex→CreateIndex đổi Code-unique filter `[IsDeleted]=0 AND [Code]<>''` cho draft-row Code="" coexist; no new table 89). **Service** `SupplierExcelImportService`: (a) re-bake ExpectedHeaderTokens BYTE-EXACT raw-`\n` form = single-source cho validator(NormalizeHeader collapse \n→space)+BuildTemplate (spec §② 30 token, c7 trailing-space); (b) dedup **MST-primary + Code-backstop** — `BuildMstIndex`(NormalizeMst=Trim+strip-inner-ws `\s+`→"" OrdinalIgnoreCase, blank→skip) precedence existing-MST→existing-Code→batch-MST→batch-Code, `countedUpdates HashSet<Supplier>` tránh double-count, blank-MST KHÔNG vào batchByMst (2 blank=2 insert); (c) BỎ hard-error blank-Code (=draft), GIỮ Name+all-or-nothing; (d) New `IsPublic=!blank(Code)`, update-path KHÔNG đụng IsPublic; +MstMissing(soft-warn) +DraftCount; (e) `BuildTemplate()` ClosedXML sheet "Sheet1" 30 token ROW4 WrapText+FreezeRows. **PublishSupplierCommand**(Id,MaNcc?,Publish): set Code+unique-CI-check + gate Publish→Code-non-empty ConflictException, KHÔNG UpdateSupplierCommand (#73 clobber). **API THẬT:** GET `/api/suppliers/import/template`(xlsx "Mau-Database-NCC.xlsx") · POST `/api/suppliers/{id}/publish` body`{maNcc?,publish}` · GET `/api/suppliers?published={t/f}` filter · SupplierDto +`bool IsPublic` append-CUỐI (sửa 2 projection List+Get). **D3 authz:** import preview/confirm/template/publish `[Roles=Admin,CatalogManager]`→`[Policy="Suppliers.Update"]` (khớp FE PermissionGuard). DbInit +IsPublic=true 4 real+18 sample. Build slnx **0/0**, apply BOTH DB (Dev catch-up+Design). KHÔNG commit/FE/test. LESSON: S112 CI-dedup-at-service mở rộng → dual-key MST-primary; blank-key KHÔNG index. Tag `[s113, supplier-import-v2, mig64, ispublic-publish-gate, dedup-mst-primary-code-backstop, blank-code-draft, buildtemplate-single-source, publish-cmd-no-#73]`.

- **2026-07-12 (S112 PE sign-off close-review implement — `wf_7df56b89-7bb` GO-WITH-ADJ, owner anh Kiệt PROD-UAT-live, 4-region/1 file `PurchaseEvaluationWorkflowService.cs`, NO mig/FE/test → ACCEPT Case 1):** **C1 A1 (`ApplyDrafterBypassOnSubmitAsync`):** người soạn KÝ TAY ô cấp mình — `k=Max`→`minOwn=Min(drafterSlots.Order)`, bypass `<=k`→`<minOwn` (chỉ NV cấp dưới THUẦN), XÓA canned-opinion UPSERT (không tự ký hộ ai) + dead `maxLevelOrder`/`ownSlot`; advance 3-nhánh→1 `if(minOwn>1){pointer=minOwn}` STOP tại minOwn (người soạn tự ApproveV2Async); minOwn=1→bypass rỗng pointer giữ (0,1); non-contiguous Cấp1+Cấp3 ký tay đúng thứ tự. **C2 EDGE-5 hard-lock:** top `TransitionAsync` sau isAdmin/isSystem TRƯỚC mọi branch → `if(fromPhase is DaDuyet or TuChoi && !isAdmin && !isSystem) throw Conflict` (chặn non-admin lật phiếu terminal; Admin+System MIỄN); KHÔNG đụng EnsureCanRejectV2Async. **C3** no self-finalize (owner oQ1 permission-driven). **C4 opinion-history (`ApproveV2Async` UPSERT else):** old.Comment→Changelog (Workflow/Update/EntityId=level.Id) TRƯỚC overwrite chỉ khi non-empty — NO mig/bảng/endpoint. Build slnx **0/0**. Infra **4 FAIL/401 pass**: fail=C1 (PeSubmitGuardAndBypassTests 9/10/12/14 assert OLD auto-sign/terminal-on-submit); C2/C4 break 0 test → test-specialist ADD. LESSON: behavior-change write-site → run consumer tests, hand VERIFIED fail-list (KHÔNG sửa test). Tag `[s112, pe-signoff, a1-sign-own-level, edge5-hardlock, opinion-history-changelog, consumer-test-verified-handoff]`.
- **2026-07-12 (S112 Supplier Excel-import Phase B BE — `wf_e2f23a84` invest-ensemble → `wf_75d6149b` close-review GO-WITH-ADJ, owner anh Kiệt, commit `e100ef0`, Mig 63 → ACCEPT Case 1/2):** **Service** `SupplierExcelImportService` (preview + confirm 2-stage) + 2 endpoint (`/suppliers/import/preview` [415 non-xlsx] · `/suppliers/import/confirm` [401 auth]) + **Mig 63 `AddSupplierImportSourceFields`** (Supplier +`SourceUpdatedAt datetime2?`+`SourceUpdatedBy nvarchar(200)?` provenance cột 29/30; 2 AddColumn nullable no-new-table 89). FE 2-app byte-identical (`SupplierImportDialog`). **LESSONS:** (1) dedup Code = **OrdinalIgnoreCase ở SERVICE** — DB unique-index CI-collation lật (SQLite fixture BINARY KHÔNG bắt, prod SQL Server CI bắt) → dedup KHÔNG dựa DB; (2) parser **absolute cell-index** (row-4 header-fingerprint), KHÔNG `CellsUsed()` (column-drift); (3) **all-or-nothing** gate TRƯỚC mutate (1 hard-error→Committed=false DB unchanged); (4) fill-nulls **SKIP Code/Name/Type** (chỉ điền field trống); (5) `.Normalize(FormC)` cho real-file NFD (close-review adjust bake 30 `RealFileHeaderTokens` byte-verify). **SURPRISE:** Approach-B (extend seed) ĐÃ ship 4 NCC prod (Mig 62) → spec "partial" SAI; import ghi entity **TRỰC TIẾP** (fill-where-non-empty) KHÔNG qua `UpdateSupplierCommand` (tránh NULL-clobber #73). Shipped Run #496 PASS, reviewer GO-WITH-ADJ (BE 6/6 axes). Tag `[s112, supplier-excel-import, mig63, ordinalignorecase-dedup-at-service, abs-cell-index-parser, all-or-nothing, fill-nulls-safe, normalize-formc-nfd, direct-entity-write]`.
- **2026-06-25 (S88 PE stability cleanup — FROZEN-module mechanical relocation + 1 stale-comment fix BE — NO migration, 3 edit/2 file, em-main spec deterministic 100% file/line/boundary given → ACCEPT Case 1):** Pure mechanical move ZERO behavior-change. **T1 misplaced-command relocate:** `SetPeCcmBudgetPeriodCommand`+Validator+Handler (BUDGET setter writes `pe.CcmBudgetPeriodAmount` Section B "NS kỳ này" CCM, Mig 59) sống NHẦM trong suggested-PRICE file → move về budget file. (a) REMOVE `PeSuggestedPriceFeatures.cs` lines 144-199 (blank + `===== CCM NS kỳ này =====` header → `SetPeCcmBudgetPeriodCommandHandler` closing `}`); file end clean tại line 143 (`UpdatePeSuggestedPriceCcmCommandHandler` `}`), suggested-price PRO/CCM trên giữ nguyên. (b) APPEND `PeWorkItemBudgetFeatures.cs` END sau line 200 (`UpdatePeBudgetCcmCommandHandler` `}`) → cạnh budget setters `UpdatePeBudgetPro/Ccm`. Code BYTE-IDENTICAL (logic/authz Admin\|CostControl fail-closed/validation GTE(0).When(HasValue)/absolute-set null=clear/changelog UNCHANGED); CHỈ prepend 1 comment line `// [S88] Chuyển từ PeSuggestedPriceFeatures.cs về đây (đúng nhóm budget setter).`. Usings 8-header IDENTICAL 2 file → KHÔNG add duplicate. Namespace `SolutionErp.Application.PurchaseEvaluations` SAME → MediatR type-resolution transparent, controller `:125` KHÔNG đụng. **T2 stale-comment fix:** `Dtos/PurchaseEvaluationDtos.cs` ~250-254 comment trên `decimal WinnerQuoteTotal` ghi SUM "của SelectedSupplierId" (OLD single-winner) → verified actual compute `PurchaseEvaluationFeatures.cs:1093-1099` = `Suppliers.Where(s=>s.IsWinner)` (multi, Mig 58) → sửa CHỈ comment-text "MỌI đơn vị IsWinner (multi-winner Mig 58)". Field/code UNCHANGED. **LESSON:** frozen-relocation = read BOTH file FIRST exact boundary + verify usings-superset target + verify stale-comment claim vs real compute-site TRƯỚC sửa (KHÔNG trust comment blind, mirror S35 EF-source-of-truth). Build `SolutionErp.Application.csproj -v q` **0 warn 0 err** (4s). KHÔNG test (test-specialist)/FE/mig/commit. Tag `[s88, frozen-relocation, byte-identical-move, mediatr-type-resolve-transparent, stale-comment-verify-compute-site, no-behavior-change]`.
- **2026-06-24 (PE Section B 3-cột THỰC HIỆN — CCM "NS kỳ này" cột riêng BE — Mig 59 `AddCcmBudgetPeriodToPurchaseEvaluation` 3-file, 5 edit/0 new file, em-main CHỐT spec+API-contract 100% → ACCEPT Case 1):** Section B tách 3 cột Dự án|PRO|CCM giống Section A. PRO=`BudgetPeriodAmount` sẵn có; CCM nhập cột riêng độc-lập. COOKIE-CUTTER mirror S77 suggested-price-Ccm + S65b HoSoLink one-column. (1) `PurchaseEvaluation.cs` +`decimal? CcmBudgetPeriodAmount` sau ExpectedRemainingAmount. (2) `PurchaseEvaluationConfiguration.cs` +`HasColumnType("decimal(18,2)")` sau ExpectedRemaining (spec asked literal decimal(18,2); siblings dùng HasPrecision(18,2) NHƯNG emit identical column — tôi follow spec verbatim HasColumnType). (3) Mig: Up=1 AddColumn decimal(18,2) nullable NO table/index, Down=1 DropColumn, snapshot verified — clean mirror Mig 52. (4) DTO `PurchaseEvaluationDetailBundleDto` +`decimal? CcmBudgetPeriodAmount` sau ExpectedRemainingAmount TRƯỚC BudgetSummary + projection PEFeatures.cs:1110 positional-insert đúng order (positional record → projection order BẮT BUỘC khít). (5) Setter `SetPeCcmBudgetPeriodCommand(Guid Id, decimal? CcmBudgetPeriodAmount):IRequest` append `PeSuggestedPriceFeatures.cs` (same concern PE role-gate setters) + Validator `GreaterThanOrEqualTo(0).When(HasValue)` (budget=0 hợp lệ) + Handler fail-closed Forbidden Admin|CostControl TRƯỚC side-effect (S56 #5) + absolute-set null=clear (gotcha #73) + changelog Header (sibling-consistency; spec min=SaveChanges). (6) Controller `[HttpPatch("{id:guid}/budget/ccm-period")]` + `CcmBudgetPeriodBody` (spec EXPLICIT PATCH dù siblings PUT — follow spec). **Call-site verify:** `new PurchaseEvaluationDetailBundleDto(` repo-wide → EXACTLY 1 (PEFeatures:1100, đã sửa) → positional-safe. Submit-guard `BudgetPeriodAmount` PRO KHÔNG đụng. Build SolutionErp.slnx (6 proj incl 2 test, gotcha #65) **0 warn 0 err**. KHÔNG apply DB/FE/test/commit. Route FE/test mirror: DTO field `ccmBudgetPeriodAmount` camelCase + PATCH `/api/purchase-evaluations/{id}/budget/ccm-period` body `{ ccmBudgetPeriodAmount }`. Tag `[pe-section-b-3col, ccm-budget-period, mig59, one-column-no-table, absolute-set-fail-closed, positional-dto-order, patch-per-spec]`.
- **2026-06-19 (PE chuông báo approver BE — NO migration, 1 edit/1 file, em-main spec deterministic 100% → ACCEPT Case 1):** Tra Sol (Zalo) "không thấy chuông — việc có hồ sơ cần duyệt": approver Cấp hiện tại KHÔNG nhận notify khi phiếu ENTER/ADVANCE tới ChoDuyet (chỉ drafter báo terminal). FIX = +1 block trong `LogTransitionAsync` (PurchaseEvaluationWorkflowService.cs ~line 1058) NGAY SAU drafter-notify, KHÔNG endpoint mới (Pattern 4 — notify = side-effect của Submit/Approve-advance, cả 2 đã gọi LogTransitionAsync + end ChoDuyet). **Resolution mirror EXACT canonical** `EnsureActorInLevel` (line ~301): `db.ApprovalWorkflows.AsNoTracking().Include(Steps).ThenInclude(Levels)` → `stepsOrdered[CurrentWorkflowStepIndex]` (bounds-check) → `.Levels.Where(Order==CurrentApprovalLevelOrder && ApproverUserId!=Guid.Empty && !=actorUserId).Select(ApproverUserId).Distinct()` → `NotifyManyAsync(ids, Generic, "Phiếu cần bạn duyệt: {MaPhieu??TenGoiThau}", "Có phiếu Duyệt NCC đang chờ bạn duyệt.", /purchase-evaluations/{Id}, refId:Id, ct)`. **Recon:** (1) `ApprovalWorkflowLevel.ApproverUserId` = non-null `Guid` (NOT Guid?) → "exclude null" = `!=Guid.Empty` defensive (OR-of-N rows mỗi 1 NV). (2) `NotifyManyAsync` sig verified = `(IEnumerable<Guid>, NotificationType, title, string? desc, string? href, Guid? refId, CT)` khớp urgent-feature ref. (3) actor-exclude qua `!= actorUserId` (Guid != Guid? lift OK). **Guard V2-only:** `ApprovalWorkflowId is Guid && CurrentWorkflowStepIndex is int && CurrentApprovalLevelOrder is int` → V1/no-workflow skip. **Best-effort try/catch** nuốt lỗi (phiếu đã SaveChanges; notify fail KHÔNG rollback). Block đọc pointer SAU set → Submit (idx0/lvl1) + Approve-advance (pointer advance rồi LogTransition) đều fire đúng. Build SolutionErp.slnx (2 test project, gotcha #65) **0 warn 0 err**. KHÔNG test/FE/mig/commit. Tag `[pe-approver-bell, notify-many, log-transition-hook, no-mig, v2-only, best-effort-trycatch, pattern4-side-effect]`.
- _(S77→S56 [2026-06-10..19, 7 entries] FIFO'd → `archive/2026-06.md` at S112; recall verbatim there / `_INDEX.md` / RAG `search_memory`.)_

---

## 🔄 Curate trigger
- >~30KB → archive recent → L2 `archive/<period>.md`. Stale >3mo → remove.
- **Last curate: 2026-07-12 S112 (implementer-backend self-FIFO, hook-triggered @24KB)** (25.6→~16KB): moved Recent-activity S77→S56 (7 entries, 2026-06-10..19) verbatim → `archive/2026-06.md` (16.7→26.4KB), kept 4 newest (S112/S88/S87/chuông). Prev **S70 Harness-9 (em-main + Stage-B)** (33.2→17.4KB): L2 dark-matter recovery — 14 Recent-activity entries (S55→S35) → NEW `archive/2026-06.md` + `_INDEX.md` (substring sha-keyed) + `2026-0{5,6}.gist.md` (distill-gen:1). 0-byte-loss md5 byte-exact (Stage C audit CONCERN → read-side-gap MEMORY-L5→_INDEX fixed). _(cosmetic: 2 curate-meta lines carry `S?` worker-label.)_ Prev: S40 (30.9→~18KB dedup-split BE/FE/test) · S34 q3 · S22 q1.
