Add edit product media action payloads

HANDOFF.md

@@ -2,11 +2,11 @@
 
 Project: `ina-trading-web`
 Current branch: `main`
-Latest verified commit: `f090ba7`
+Latest verified commit: current `HEAD` after the product edit media-action payload update
 
 ## 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, sanitized backend error display, AddProductRequest validation, and 10 MB upload limits.
+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, 10 MB upload limits, and edit-product media action payloads.
 
 Latest local verification before the newest push:
 
@@ -26,6 +26,46 @@ Latest TypeScript verification after the validation/upload changes:
 npx tsc --noEmit
 ```
 
+## Latest Codex Changes After `84c81d4`
+
+### Product edit media action payloads
+
+Files:
+- `src/app/(dashboard)/products/[productId]/edit/page.tsx`
+- `src/lib/product-request-validation.ts`
+
+Behavior:
+- Edit-product now captures the original product media snapshot when the product is loaded.
+- Existing product save (`PUT /api/products/:productId`) now sends media changes using backend action markers:
+  - `ADD`
+  - `UPDATE`
+  - `DELETE`
+- `productFiles` now sends:
+  - deleted original files as `{ fileId, action: "DELETE" }`
+  - newly uploaded files as `{ fileId, action: "ADD" }`
+- `productImages` now sends changed image rows with `{ imageId, sequence, action }`.
+  - replacing an image in an existing slot sends `UPDATE`
+  - removing an original image sends `DELETE`
+  - adding a new image sends `ADD`
+- `complianceInformation` now includes an `action` when the compliance/MSDS file changes:
+  - no old file + new file: `ADD`
+  - old file + no current file: `DELETE`
+  - old file replaced by new file: `UPDATE`
+- Draft publish/create flow still keeps the previous create payload shape so `POST /api/products/create` is not changed.
+- Product payload validation now supports both old `productFiles: string[]` and new `productFiles: { fileId, action }[]` shapes.
+
+Verification:
+
+```bash
+npx tsc --noEmit
+npx eslint 'src/app/(dashboard)/products/[productId]/edit/page.tsx' src/lib/product-request-validation.ts
+```
+
+Notes:
+- Targeted lint passed with no errors.
+- The edit page still has existing `<img>` optimization warnings from Next.js.
+- Full `npm run lint` is still blocked by pre-existing lint errors in unrelated files noted before this handoff update.
+
 ## Latest Codex Changes After `4e28ccd`
 
 ### Admin review image dedupe