Fix frontend port configuration: Update Dockerfile to use port 806

- Changed EXPOSE from 3000 to 806
- Added PORT=806 environment variable
- Updated health check to use port 806
- Fixes admin login network error by aligning with docker-compose.yml 806:806 mapping

frontend/Dockerfile

@@ -19,11 +19,14 @@ COPY . .
 RUN pnpm build
 
 # Expose port
-EXPOSE 3000
+EXPOSE 806
+
+# Set port environment variable
+ENV PORT=806
 
 # Health check
 HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
-  CMD curl -f http://localhost:3000 || exit 1
+  CMD curl -f http://localhost:806 || exit 1
 
 # Start the application
 CMD ["pnpm", "start"]