This commit adds a new web proxy server feature to wssshd that:
- Adds --web-proxy [PORT] command line option (default port: 9090)
- Listens on 127.0.0.1 only for security
- Proxies HTTP requests to registered clients based on hostname
- Supports multiple concurrent connections

Changes:
- config.h: Add web_proxy_enabled and web_proxy_port fields
- config.c: Add --web-proxy option parsing and config file support
- web_proxy.h: New header with function declarations
- web_proxy.c: New implementation with TCP server and hostname-based routing
- main.c: Add web_proxy_start/stop_server calls
- wssshd.1: Update man page with new option
- README.md: Add documentation for web proxy feature