Add product request validation and upload limits

HANDOFF.md

@@ -2,11 +2,11 @@
 
 Project: `ina-trading-web`
 Current branch: `main`
-Latest verified commit: `aa406f5`
+Latest verified commit: `9b4e5d7`
 
 ## Summary
 
-This codebase has recent updates around auth/onboarding, help/privacy pages, dashboard search, product creation/edit/review/detail, admin review/detail, stock/price editing, seller in-review listing, backend request logging, expired-session redirects, product keyword limits, and sanitized backend error display.
+This codebase has recent updates around auth/onboarding, help/privacy pages, dashboard search, product creation/edit/review/detail, admin review/detail, stock/price editing, seller in-review listing, backend request logging, expired-session redirects, product keyword limits, sanitized backend error display, AddProductRequest validation, and 10 MB upload limits.
 
 The latest build was verified successfully with:
 
@@ -14,13 +14,62 @@ The latest build was verified successfully with:
 npm run build
 ```
 
-Latest TypeScript verification after `aa406f5`:
+Latest TypeScript verification after the validation/upload changes:
 
 ```bash
 npx tsc --noEmit
 ```
 
-## Latest Codex Changes After `aa406f5`
+## Latest Codex Changes After `76fb4f3`
+
+### AddProductRequest validation
+
+Files:
+- `src/lib/product-request-validation.ts`
+- `src/lib/use-product-submit.ts`
+- `src/app/(dashboard)/products/[productId]/edit/page.tsx`
+- `src/app/(dashboard)/products/new/details/page.tsx`
+- `src/app/(dashboard)/products/new/pricing/page.tsx`
+- `src/app/(dashboard)/products/new/specifications/page.tsx`
+- `src/lib/product-draft.tsx`
+
+Behavior:
+- Added a shared validator for create/edit product payloads before requests are sent to backend.
+- Validates the backend `AddProductRequest` limits for:
+  - basic product fields
+  - image/file IDs
+  - keywords max 3 and features max 5
+  - model fields, currencies, SKU, package fields
+  - numeric weight/dimension/package fields max 9 digits plus 1 decimal
+  - warehouse IDs max 50 and stock minimal 1
+  - measurement fields, measurement warehouses, and measurement stock
+  - product/category information param name/value limits
+  - compliance information limits
+  - warranty type max 50 and duration minimal 1 when warranty is filled
+- Existing wizard drafts normalize keywords to max 3 and features to max 5.
+- Create-product UI now shows visible validation-limit panels on:
+  - Details
+  - Pricing
+  - Specifications
+- Relevant inputs also received direct hints/limits such as max product name length, keyword/feature limits, pre-order minimum, warranty minimum, and upload limit text.
+
+### Upload file size limit
+
+Files:
+- `src/lib/upload-limits.ts`
+- `src/app/api/upload/route.ts`
+- `src/components/upload-field.tsx`
+- `src/app/(dashboard)/products/new/specifications/page.tsx`
+- `src/app/(dashboard)/products/[productId]/edit/page.tsx`
+- `src/app/(onboarding)/onboarding/business/page.tsx`
+
+Behavior:
+- Uploads are limited to 10 MB per file.
+- Client-side checks reject oversized files before upload in shared upload fields, product create/edit document uploads, and onboarding legal document upload.
+- Server-side `/api/upload` rejects oversized files with HTTP `413` and a safe `responseDesc`.
+- User-facing helper text now mentions the 10 MB limit for document uploads.
+
+## Previous Codex Changes After `aa406f5`
 
 ### Backend URL