Improved Async Cleanup for Proxy Servers

What: Proxy server cleanup is now properly awaited and handles both HTTP and SOCKS5 proxies.

Details:

• Function YC0() at line 375687 now uses Promise.all() to wait for all proxies to shut down
• HTTP proxy cleanup properly awaited instead of fire-and-forget
• SOCKS proxy cleanup added for the new proxy type (lines 375714-375722)
• Both proxies shut down in parallel for faster cleanup
• Prevents race conditions and leaked proxy processes during shutdown
• Evidence: YC0() at line 375687 changed from synchronous to async with Promise-based cleanup

Impact: More reliable shutdown process with no leaked background processes.