Drop attached_assets folder

Removes 7 unused PNGs (Replit-generated screenshots) plus the matching
@assets Vite alias and the docker/web.Dockerfile copy step. Nothing
in the source code imported from this alias.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

artifacts/cra-app/vite.config.ts

@@ -31,7 +31,6 @@ export default defineConfig({
   resolve: {
     alias: {
       "@": path.resolve(import.meta.dirname, "src"),
-      "@assets": path.resolve(import.meta.dirname, "..", "..", "attached_assets"),
     },
     dedupe: ["react", "react-dom"],
   },

docker/web.Dockerfile

@@ -19,7 +19,6 @@ RUN pnpm install --frozen-lockfile
 FROM deps AS build
 COPY lib lib
 COPY artifacts/cra-app artifacts/cra-app
-COPY attached_assets attached_assets
 ENV NODE_ENV=production
 ENV PORT=80
 ENV BASE_PATH=/