feat(po-detail): show all attachments grouped by type

Split the flat document list into two labeled sections: Submission
(po-document/* keys) and Delivery Receipt (receipt/* keys). Delivery
notes from the Receipt record are also surfaced under that section.
Added `receipt` to the PoWithRelations type so the field is available
inside the component.

Fixes #10

App/components/po/po-detail.tsx

@@ -65,6 +65,7 @@ type PoWithRelations = {
     sortOrder: number;
   }[];
   documents: { id: string; fileName: string; fileSize: number; storageKey: string; uploadedAt: Date }[];
+  receipt: { id: string; storageKey: string; fileName: string; notes: string | null; confirmedAt: Date } | null;
   actions: { id: string; actionType: string; note: string | null; metadata: import("@prisma/client").Prisma.JsonValue; createdAt: Date; actor: { name: string } }[];
 };
 
@@ -149,9 +150,10 @@ export async function PoDetail({ po, currentUserId, currentRole, readOnly = fals
     ? "Submitter updated these line items after edits were requested. Previous values shown with strikethrough."
     : "Line items were amended by manager. Current values shown; original values shown with strikethrough.";
 
-  const downloadUrls = await Promise.all(
+  const downloadUrlList = await Promise.all(
     po.documents.map((doc) => generateDownloadUrl(doc.storageKey))
   );
+  const urlByDocId = new Map(po.documents.map((doc, i) => [doc.id, downloadUrlList[i]]));
 
   const canConfirmReceipt =
     (po.status === "PAID_DELIVERED" || po.status === "PARTIALLY_CLOSED" || po.status === "PARTIALLY_PAID") &&
@@ -399,15 +401,19 @@ export async function PoDetail({ po, currentUserId, currentRole, readOnly = fals
         </div>
       )}
 
-      {/* Documents */}
+      {/* Documents — grouped by type */}
-      {po.documents.length > 0 && (
+      {(() => {
-        <div className="rounded-lg border border-neutral-200 bg-white p-6">
+        const submissionDocs = po.documents.filter((d) => !d.storageKey.startsWith("receipt/"));
-          <h3 className="text-sm font-semibold text-neutral-900 mb-4">Attachments</h3>
+        const receiptDocs = po.documents.filter((d) => d.storageKey.startsWith("receipt/"));
+        const hasDeliverySection = receiptDocs.length > 0 || !!po.receipt?.notes;
+        if (submissionDocs.length === 0 && !hasDeliverySection) return null;
+
+        const renderDocList = (docs: typeof po.documents) => (
           <ul className="space-y-2">
-            {po.documents.map((doc, i) => (
+            {docs.map((doc) => (
               <li key={doc.id} className="flex items-center gap-3 text-sm">
                 <a
-                  href={downloadUrls[i]}
+                  href={urlByDocId.get(doc.id)}
                   target="_blank"
                   rel="noopener noreferrer"
                   className="font-medium text-primary-600 hover:underline"
@@ -420,8 +426,31 @@ export async function PoDetail({ po, currentUserId, currentRole, readOnly = fals
               </li>
             ))}
           </ul>
-        </div>
+        );
-      )}
+
+        return (
+          <div className="rounded-lg border border-neutral-200 bg-white p-6">
+            <h3 className="text-sm font-semibold text-neutral-900 mb-4">Attachments</h3>
+            <div className="space-y-5">
+              {submissionDocs.length > 0 && (
+                <div>
+                  <p className="text-xs font-medium text-neutral-500 uppercase tracking-wide mb-2">Submission</p>
+                  {renderDocList(submissionDocs)}
+                </div>
+              )}
+              {hasDeliverySection && (
+                <div>
+                  <p className="text-xs font-medium text-neutral-500 uppercase tracking-wide mb-2">Delivery Receipt</p>
+                  {po.receipt?.notes && (
+                    <p className="text-sm text-neutral-600 italic mb-2">&ldquo;{po.receipt.notes}&rdquo;</p>
+                  )}
+                  {receiptDocs.length > 0 && renderDocList(receiptDocs)}
+                </div>
+              )}
+            </div>
+          </div>
+        );
+      })()}
 
       {/* Confirm receipt CTA */}
       {canConfirmReceipt && (