feat(cart): header cart icon with badge + fix PO pre-population from cart

Cart icon:
- CartIcon component in header: listens to cart-updated events, shows
  item count badge, navigates to /inventory/cart on click
- Visible for TECHNICAL, MANNING, SUPERUSER, MANAGER roles only

PO pre-population:
- /po/new page reads ?cart= searchParam, parses CartItem[] into
  LineItemInput[], passes as initialLineItems prop to NewPoForm
- NewPoForm accepts initialLineItems and seeds useState from them
  instead of always starting with one blank row
- Cart is cleared immediately when "Create Purchase Order" is clicked
  so re-visiting cart doesn't re-submit the same items

Cart fixes:
- Empty state and "Add more items" links corrected from /admin/products
  to /inventory/items and /inventory/vendors

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

App/pelagia-portal/app/(portal)/inventory/cart/cart-view.tsx

@@ -31,8 +31,9 @@ export function CartView() {
   }
 
   function createPO() {
-    // Encode cart into query params and navigate to new PO with prefill
     const encoded = encodeURIComponent(JSON.stringify(items));
+    clearCart();
+    setItems([]);
     router.push(`/po/new?cart=${encoded}`);
   }
 
@@ -45,8 +46,8 @@ export function CartView() {
         <p className="text-neutral-500 font-medium">Your cart is empty</p>
         <p className="text-sm text-neutral-400 mt-1 mb-6">Browse Items or Vendors to add line items</p>
         <div className="flex gap-3 justify-center">
-          <Link href="/admin/products" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">Browse Items</Link>
+          <Link href="/inventory/items" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">Browse Items</Link>
-          <Link href="/admin/vendors" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">Browse Vendors</Link>
+          <Link href="/inventory/vendors" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">Browse Vendors</Link>
         </div>
       </div>
     );
@@ -107,7 +108,7 @@ export function CartView() {
       <div className="flex items-center justify-between">
         <button onClick={() => { clearCart(); setItems([]); }} className="text-sm text-danger-600 hover:underline">Clear cart</button>
         <div className="flex gap-3">
-          <Link href="/admin/products" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">
+          <Link href="/inventory/items" className="rounded-lg border border-neutral-300 px-4 py-2 text-sm font-medium text-neutral-700 hover:bg-neutral-50">
             + Add more items
           </Link>
           <button onClick={createPO} className="rounded-lg bg-primary-600 px-5 py-2 text-sm font-semibold text-white hover:bg-primary-700">

App/pelagia-portal/app/(portal)/po/new/new-po-form.tsx

@@ -13,17 +13,20 @@ import { TC_DEFAULTS, TC_FIXED_LINE, TC_FIXED_LINE_2 } from "@/lib/validations/p
 const INPUT_CLS =
   "w-full rounded-lg border border-neutral-300 px-3 py-2.5 text-sm focus:border-primary-500 focus:outline-none focus:ring-2 focus:ring-primary-500/20";
 
+const EMPTY_LINE: LineItemInput = { name: "", description: "", quantity: 1, unit: "pc", size: "", unitPrice: 0, gstRate: 0.18 };
+
 interface Props {
   vessels: Vessel[];
   accounts: Account[];
   vendors: Vendor[];
+  initialLineItems?: LineItemInput[];
 }
 
-export function NewPoForm({ vessels, accounts, vendors }: Props) {
+export function NewPoForm({ vessels, accounts, vendors, initialLineItems }: Props) {
   const router = useRouter();
-  const [lineItems, setLineItems] = useState<LineItemInput[]>([
+  const [lineItems, setLineItems] = useState<LineItemInput[]>(
-    { name: "", description: "", quantity: 1, unit: "pc", size: "", unitPrice: 0, gstRate: 0.18 },
+    initialLineItems && initialLineItems.length > 0 ? initialLineItems : [EMPTY_LINE]
-  ]);
+  );
   const [files, setFiles] = useState<File[]>([]);
   const [submitting, setSubmitting] = useState<"draft" | "submit" | null>(null);
   const [error, setError] = useState("");

App/pelagia-portal/app/(portal)/po/new/page.tsx

@@ -4,10 +4,16 @@ import { hasPermission } from "@/lib/permissions";
 import { redirect } from "next/navigation";
 import { NewPoForm } from "./new-po-form";
 import type { Metadata } from "next";
+import type { LineItemInput } from "@/lib/validations/po";
+import type { CartItem } from "@/lib/cart";
 
 export const metadata: Metadata = { title: "New Purchase Order" };
 
-export default async function NewPoPage() {
+interface Props {
+  searchParams: Promise<{ cart?: string }>;
+}
+
+export default async function NewPoPage({ searchParams }: Props) {
   const session = await auth();
   if (!session?.user) redirect("/login");
 
@@ -15,6 +21,29 @@ export default async function NewPoPage() {
     redirect("/dashboard");
   }
 
+  const { cart } = await searchParams;
+
+  let initialLineItems: LineItemInput[] | undefined;
+  if (cart) {
+    try {
+      const cartItems: CartItem[] = JSON.parse(decodeURIComponent(cart));
+      if (Array.isArray(cartItems) && cartItems.length > 0) {
+        initialLineItems = cartItems.map((item) => ({
+          name: item.name,
+          description: item.description ?? "",
+          quantity: item.quantity,
+          unit: item.unit,
+          size: "",
+          unitPrice: item.unitPrice,
+          gstRate: 0.18,
+          productId: item.productId,
+        }));
+      }
+    } catch {
+      // malformed cart param — ignore and start empty
+    }
+  }
+
   const [vessels, accounts, vendors] = await Promise.all([
     db.vessel.findMany({ where: { isActive: true }, orderBy: { name: "asc" } }),
     db.account.findMany({ where: { isActive: true }, orderBy: { name: "asc" } }),
@@ -29,7 +58,7 @@ export default async function NewPoPage() {
           Fill in the details below. You can save as draft or submit directly for approval.
         </p>
       </div>
-      <NewPoForm vessels={vessels} accounts={accounts} vendors={vendors} />
+      <NewPoForm vessels={vessels} accounts={accounts} vendors={vendors} initialLineItems={initialLineItems} />
     </div>
   );
 }

App/pelagia-portal/components/layout/cart-icon.tsx

@@ -0,0 +1,33 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useRouter } from "next/navigation";
+import { ShoppingCart } from "lucide-react";
+import { getCart } from "@/lib/cart";
+
+export function CartIcon() {
+  const router = useRouter();
+  const [count, setCount] = useState(0);
+
+  useEffect(() => {
+    const update = () => setCount(getCart().reduce((s, i) => s + i.quantity, 0));
+    update();
+    window.addEventListener("cart-updated", update);
+    return () => window.removeEventListener("cart-updated", update);
+  }, []);
+
+  return (
+    <button
+      onClick={() => router.push("/inventory/cart")}
+      title="Cart"
+      className="relative flex items-center justify-center rounded-lg p-2 text-neutral-500 hover:bg-neutral-100 hover:text-neutral-700 transition-colors"
+    >
+      <ShoppingCart className="h-4 w-4" />
+      {count > 0 && (
+        <span className="absolute -top-0.5 -right-0.5 flex h-4 w-4 items-center justify-center rounded-full bg-primary-600 text-[10px] font-bold text-white leading-none">
+          {count > 99 ? "99+" : count}
+        </span>
+      )}
+    </button>
+  );
+}

App/pelagia-portal/components/layout/header.tsx

@@ -3,6 +3,7 @@
 import { signOut } from "next-auth/react";
 import { LogOut } from "lucide-react";
 import type { Role } from "@prisma/client";
+import { CartIcon } from "./cart-icon";
 
 const ROLE_LABELS: Record<Role, string> = {
   TECHNICAL: "Technical",
@@ -14,6 +15,8 @@ const ROLE_LABELS: Record<Role, string> = {
   ADMIN: "Admin",
 };
 
+const CART_ROLES: Role[] = ["TECHNICAL", "MANNING", "SUPERUSER", "MANAGER"];
+
 interface HeaderProps {
   user: { name: string; email: string; role: Role };
 }
@@ -22,8 +25,9 @@ export function Header({ user }: HeaderProps) {
   return (
     <header className="flex h-16 items-center justify-between border-b border-neutral-200 bg-white px-6">
       <div />
-      <div className="flex items-center gap-4">
+      <div className="flex items-center gap-2">
-        <div className="text-right">
+        {CART_ROLES.includes(user.role) && <CartIcon />}
+        <div className="text-right ml-2">
           <p className="text-sm font-medium text-neutral-900">{user.name}</p>
           <p className="text-xs text-neutral-500">{ROLE_LABELS[user.role]}</p>
         </div>