Initial marketplace implementation

Full-stack marketplace for buying/selling second-hand items.
React 19 + TypeScript + Tailwind CSS v4 frontend with 17 screens,
Express + Prisma + Socket.io backend, Stripe payments, JWT auth.

Deployed at https://marketplace.173.212.212.157.sslip.io/

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

server/src/validators/listing.ts

@@ -0,0 +1,13 @@
+import { z } from 'zod';
+
+export const createListingSchema = z.object({
+  title: z.string().min(3, 'Title must be at least 3 characters').max(100),
+  description: z.string().min(10, 'Description must be at least 10 characters').max(2000),
+  price: z.number().positive('Price must be positive'),
+  obo: z.boolean().optional().default(false),
+  category: z.enum(['ELECTRONICS', 'FURNITURE', 'CLOTHING', 'HOME_GARDEN', 'SPORTS', 'BOOKS', 'GAMES', 'VEHICLES', 'OTHER']),
+  condition: z.enum(['NEW', 'LIKE_NEW', 'GENTLY_USED', 'USED', 'FAIR']),
+  location: z.string().min(2, 'Location is required'),
+});
+
+export const updateListingSchema = createListingSchema.partial();