Add design approval workflow and per-image dimension tracking

- Add DesignApproval and DesignApprovalMessage models for design review workflow
- Add design approval admin interface (list, detail, chat, approve/reject)
- Add per-image dimension tracking to OrderItem
- Add design submission API endpoint
- Add AdminDesignEditor for admin-side design modifications
- Add DesignApprovalChat component for customer-admin communication
- Update design specification generation with image dimension details
- Add design persistence across login with next parameter redirect
- Add font properties UI with font size and color display

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

src/app/api/designs/pending/route.ts

@@ -0,0 +1,20 @@
+import { NextResponse } from 'next/server';
+import { prisma } from '@/lib/prisma';
+
+export async function GET() {
+  try {
+    const designs = await prisma.designApproval.findMany({
+      where: { status: 'PENDING' },
+      include: { product: true, messages: { orderBy: { createdAt: 'desc' }, take: 1 } },
+      orderBy: { createdAt: 'desc' },
+    });
+
+    return NextResponse.json(designs);
+  } catch (err) {
+    console.error('Error fetching pending designs:', err);
+    return NextResponse.json(
+      { error: 'Failed to fetch pending designs' },
+      { status: 500 }
+    );
+  }
+}