Fix product image gallery and submenu navigation

HANDOFF.md

@@ -8,6 +8,12 @@ Latest verified commit: `f090ba7`
 
 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.
 
+Latest local verification before the newest push:
+
+```bash
+npm run build
+```
+
 The latest build was verified successfully with:
 
 ```bash
@@ -20,6 +26,60 @@ Latest TypeScript verification after the validation/upload changes:
 npx tsc --noEmit
 ```
 
+## Latest Codex Changes After `2cfff02`
+
+### Product edit image payload preservation
+
+File:
+- `src/app/(dashboard)/products/[productId]/edit/page.tsx`
+
+Behavior:
+- Edit-product save keeps `imageId` as the main image field.
+- If the main image already exists inside `productImages`, the save payload preserves it at the same sequence.
+- If the main image is replaced, the old main image entry inside `productImages` is replaced with the new `imageId` at the same sequence.
+- The edit gallery UI hides duplicate thumbnails where `form.imageId` is also present in `form.productImages`, but the underlying array is preserved for payload sequence.
+
+Expected image payload shape:
+
+```json
+{
+  "imageId": "imageBaru.jpg",
+  "productImages": [
+    { "imageId": "gallery-0.jpg", "sequence": 1 },
+    { "imageId": "imageBaru.jpg", "sequence": 2 },
+    { "imageId": "gallery-2.jpg", "sequence": 3 }
+  ]
+}
+```
+
+### Product detail image gallery
+
+Files:
+- `src/app/(dashboard)/products/[productId]/detail/page.tsx`
+- `src/components/product-variant-showcase.tsx`
+- `src/lib/product-variants.ts`
+
+Behavior:
+- Product detail image thumbnails are deduplicated between root `imageId` and `productImages`.
+- Thumbnail strip is horizontally scrollable when there are many images.
+- Clicking a thumbnail updates the large preview image.
+- The active thumbnail receives a visible selected state.
+
+### Product submenu click lock fix
+
+Files:
+- `src/app/(dashboard)/layout.tsx`
+- `src/app/(dashboard)/products/page.tsx`
+- `src/components/product-submenu-nav.tsx`
+
+Behavior:
+- Product submenu items now use Next `<Link>` instead of manual `button` + `router.push`.
+- `All Product` now navigates to `/products?tab=all`, matching the query-based pattern used by the other submenu tabs.
+- Product API already normalizes `tab=all` to the all-product backend endpoint.
+- Sidebar z-index was raised above product modals so submenu clicks are not blocked by stale overlays.
+- Product list clears action-menu and modal state when tab/page changes.
+- Delete/unpublish/stock-price-load errors now close the related modal after showing the error, preventing a full-screen overlay from trapping sidebar clicks.
+
 ## Latest Codex Changes After `76fb4f3`
 
 ### Product create preorder and warranty submit rules
@@ -602,13 +662,13 @@ pm2 save
 sudo -iu inadev pm2 status
 ```
 
-Current expected deployed commit after latest push:
+Current expected deployed commit after latest push is the latest `origin/main` commit from this handoff update. Verify short hash with:
 
 ```bash
-2f64282
+git rev-parse --short HEAD
 ```
 
-Verify on server:
+Verify full commit on server:
 
 ```bash
 git rev-parse HEAD