feat: Implement fixed sale price functionality for items

- Added a toggle for fixed sale price vs stock value in the item creation form.
- Introduced validation to ensure all variants have a price greater than 0 when fixed price mode is selected.
- Updated the item model to include a nullable salePrice field, which is used for sales only and does not affect GRN/FIFO/ledger.
- Enhanced the GRN page to allow off-PO items and included a refresh button to update the item list without reloading the page.
- Updated documentation to reflect changes in item pricing and GRN handling.

Frontend/PROGRESS.md

@@ -27,7 +27,7 @@ Convention: `docs/01-DOC-GUIDE.md §6`. Update this file in the **same commit**
 - [~] Forgot password — change password screen — UI built (`app/login/forgot/reset`); not yet wired to API
 
 ## 2. Master Data screens
-- [~] Items (`app/dashboard/products` list + filters, `/new` create, `/[id]` full edit + ETag/If-Match with 412-conflict handling + activate/deactivate) — FR-MD-01/08. Reused the pre-existing "Products" sidebar entry/stub route rather than adding a new nav item. **2026-07-15, rebuilt twice this session — see the two same-day entries below for the full history; current state:** `/new` is now Category → Subcategory (always visible, disabled with "No subcategories" when the category has none) → Brand → a checkbox-driven **variant builder** sourced live from `variantCategoriesApi`, with no SKU/Name/Description/Default vendor/Tax class/Item type/Tracking mode/Base UOM fields left on the form at all (Item type/tracking mode/base UOM are now fixed constants — `"Stocked"`/`"None"`/`uomId 1` — baked into the submit call, not user-facing). Checking a category (Color, Size, or any custom one) reveals its value-entry UI; Color gets a native color picker + a required name field (stored internally as `"name|hex"`, decoded everywhere it's displayed/used for SKU) while every other category is free-text chips. A flat table (one column per checked category + SKU + Quantity) generalizes to any number of active categories via a cartesian-product `useMemo`, replacing the earlier hardcoded 2-column Color×Size matrix. Submitting loops `itemsApi.create()` once per combination; SKU is `<CategoryCode>-<value1Code>-<value2Code>...`; item name is `<Brand> <Category> - <value1>/<value2>...`. Added optional `brandId`/`initialQty` to `Item`/`CreateItemRequest`/`ItemListItem` (`types/master-data.ts`) — **deviation:** neither field is in the documented Item DTO (`docs/11-BACKEND-PHASE1.md` §2.1); `initialQty` is captured but not wired into the Stock Core ledger (informational only, no warehouse/GRN behind it).
+- [~] Items (`app/dashboard/products` list + filters, `/new` create, `/[id]` full edit + ETag/If-Match with 412-conflict handling + activate/deactivate) — FR-MD-01/08. **2026-07-22:** `/new` gained a **"Fixed price / Use stock value" sale-price toggle** — see the 2026-07-22 entry. Reused the pre-existing "Products" sidebar entry/stub route rather than adding a new nav item. **2026-07-15, rebuilt twice this session — see the two same-day entries below for the full history; current state:** `/new` is now Category → Subcategory (always visible, disabled with "No subcategories" when the category has none) → Brand → a checkbox-driven **variant builder** sourced live from `variantCategoriesApi`, with no SKU/Name/Description/Default vendor/Tax class/Item type/Tracking mode/Base UOM fields left on the form at all (Item type/tracking mode/base UOM are now fixed constants — `"Stocked"`/`"None"`/`uomId 1` — baked into the submit call, not user-facing). Checking a category (Color, Size, or any custom one) reveals its value-entry UI; Color gets a native color picker + a required name field (stored internally as `"name|hex"`, decoded everywhere it's displayed/used for SKU) while every other category is free-text chips. A flat table (one column per checked category + SKU + Quantity) generalizes to any number of active categories via a cartesian-product `useMemo`, replacing the earlier hardcoded 2-column Color×Size matrix. Submitting loops `itemsApi.create()` once per combination; SKU is `<CategoryCode>-<value1Code>-<value2Code>...`; item name is `<Brand> <Category> - <value1>/<value2>...`. Added optional `brandId`/`initialQty` to `Item`/`CreateItemRequest`/`ItemListItem` (`types/master-data.ts`) — **deviation:** neither field is in the documented Item DTO (`docs/11-BACKEND-PHASE1.md` §2.1); `initialQty` is captured but not wired into the Stock Core ledger (informational only, no warehouse/GRN behind it).
 - [~] UOM + conversions (`app/dashboard/products/uoms` flat list + create dialog; conversions edited inline on the Item detail page via `PUT /items/{itemId}/uom-conversions`) — FR-MD-02/03
 - [~] Categories (`app/dashboard/products/categories` indented tree view + create dialog with parent picker) — FR-MD-04. **2026-07-15:** added debounced search + Previous/Next pagination (`categoriesApi.list()` now takes `page`/`pageSize`/`q`/`sortOrder`, page size 5), matching the Vendor list's pagination pattern.
 - [~] Brands (`app/dashboard/products/brands` list + create/edit dialog + delete) — **not a documented FR/endpoint**; `lib/api/brands.ts` treats it as a standalone name-only master, same shape as Categories, since Item has no `brandId` in the doc. **2026-07-15:** added the same debounced search + pagination as Categories; `Item`/`CreateItemRequest`/`ItemListItem` gained `brandId` so the new-item variant builder (above) can attach a brand.
@@ -44,7 +44,7 @@ Convention: `docs/01-DOC-GUIDE.md §6`. Update this file in the **same commit**
 
 ## 4. Receiving screens
 - [~] GRN list (`app/dashboard/receiving/grn/page.tsx`) — loading/empty/error states, links to detail
-- [~] GRN create (`app/dashboard/receiving/grn/new/page.tsx`) — "Against PO" (picks an Approved/PartiallyReceived PO, prefills open lines) and "Direct receipt" (vendor + manual lines) modes; per-line bin, qty, unit cost, **discount % / VAT %** (with live after-discount/after-VAT line total + a per-row PO-price variance hint and a document total), hold status, and batch (batchNo+expiryDate) or serial-number-list capture driven by the item's `trackingMode`. **2026-07-20:** discount/VAT/variance added — see the 2026-07-20 entry.
+- [~] GRN create (`app/dashboard/receiving/grn/new/page.tsx`) — "Against PO" (picks an Approved/PartiallyReceived PO, prefills open lines) and "Direct receipt" (vendor + manual lines) modes; per-line bin, qty, unit cost, **discount % / VAT %** (with live after-discount/after-VAT line total + a per-row PO-price variance hint and a document total), hold status, and batch (batchNo+expiryDate) or serial-number-list capture driven by the item's `trackingMode`. **2026-07-20:** discount/VAT/variance added — see the 2026-07-20 entry. **2026-07-22:** "Add line" now works in **PO mode** (off-PO items) + **"New item"** (opens `/dashboard/products/new` in a new tab) + **refresh** icon — see the 2026-07-22 entry.
 - [~] GRN confirm (`app/dashboard/receiving/grn/[id]/page.tsx`) — renders returned `createdLayers`/`ledgerRefs`/`poStatus` as a confirmation panel (20-FRONTEND §4); sends a stable `Idempotency-Key` per detail-page session
 - [~] Inspection hold release / reject — Release/Reject buttons per on-hold line, shown once the GRN is `Confirmed`
 - Sidebar: added "Receiving" nav entry (`components/Layouts/AppSidebar.tsx`) → `/dashboard/receiving/grn`
@@ -90,6 +90,11 @@ Convention: `docs/01-DOC-GUIDE.md §6`. Update this file in the **same commit**
 ## Done
 <!-- move [x] items here with date + note if the active list grows long -->
 
+### 2026-07-22 — Item fixed sale price + GRN off-PO items / inline create
+- **Item sale-price toggle** (`app/dashboard/products/new/page.tsx`). New "Fixed price / Use stock value" segmented toggle (default **stock**). **Stock** sends `salePrice: null` on every created item. **Fixed** reveals a top "fix value" input that pre-fills a per-variant **Sale price** column (`priceFor(key) = pricesByKey[key] ?? fixValue`, so editing a row overrides only it while the rest follow the shared value); submit is blocked until **every** generated variant has a price `> 0` (`validateVariantPrices` in `lib/validations/master-data.ts`). Each variant's price rides its own `POST /items` in the existing non-transactional create loop. `types/master-data.ts`: `salePrice` added to `CreateItemRequest` (optional) and `Item`/`ItemListItem` (`number|null`).
+- **GRN off-PO items + inline create** (`app/dashboard/receiving/grn/new/page.tsx`). "Add line" is now shown in **both** PO and direct mode — an added PO-mode line has `poLineId: null` (editable item/UOM, `unitCost` required) and the server receives it as a direct line. New **"New item"** button opens `/dashboard/products/new` in a new browser tab (`window.open(..., "_blank", "noopener,noreferrer")` — the first new-tab pattern in the app), and a **refresh** icon (`refreshItems`) re-pulls `GET /items?status=Active` so the new item is selectable without reloading the in-progress GRN. Existing `validateLine` covers off-PO lines unchanged.
+- **Verified:** `tsc --noEmit` clean. Runtime browser verification (create fixed-priced variants; add an off-PO line + inline item on a PO GRN) is the next step.
+
 ### 2026-07-20 — PO draft lifecycle + GRN discount/VAT/price-override (backend + frontend, same pass)
 - **PO draft lifecycle.** `lib/api/purchase-orders.ts`: `isPoEditable` narrowed to `status === "Draft"` (was the three-status exclusion); added `submit(poId)` and `remove(poId)`. `types/procurement.ts`: `saveAsDraft?` on `CreatePurchaseOrderRequest`; `UpdatePurchaseOrderRequest` now `Omit`s it. `/new`: the single "Create PO" button split into **Save as draft** / **Create & submit**. `/[id]`: **Draft** shows the editable line grid + **Submit** + **Delete draft**; an issued-but-open PO (`Approved`/`PartiallyReceived`) is read-only with **Cancel PO** (with reason, disabled once receipts exist); closed/cancelled are terminal. The old Cancel button was gated on `isPoEditable` — that would have shown Cancel only for Draft, so the affordances were re-split into `editable` (Draft) vs `cancellable` (Approved/PartiallyReceived).
 - **GRN discount/VAT/variance.** `types/grn.ts`: `discountPct`/`vatPct` on `CreateGrnLineInput`; `poUnitPrice`/`discountPct`/`netUnitCost`/`vatPct`/`vatAmount`/`lineTotal`/`priceVariance` on `GrnLine`. `/new`: per-line Disc %/VAT % inputs, a client mirror of the server arithmetic (`computeLine`, display-only — server stays authoritative) driving a live Line total + document total, and a PO-price variance hint when the entered unit cost differs from the prefilled PO price. `/[id]`: renders the full cost breakdown (unit cost + variance, disc %, net cost, received value, VAT, line total) and a stock-value/VAT/document-total footer. `lib/validations/grn.ts`: 0–100 range checks on the two percentages.