c2w-net: add dynamic port forwarding for WebSocket mode

[maceip]

Summary

Enables port forwarding (-p flag) in --listen-ws mode by dynamically querying DHCP leases to discover the actual container IP address, removing the need for hardcoded values or static MAC-to-IP mappings.

Changes

• Query gvisor-tap-vsock's internal /services/dhcp/leases endpoint to discover container IP
• Poll every 200ms for up to 10 seconds to detect when container receives DHCP lease
• Automatically start port forwarders once container IP is discovered
• Remove all IP address guessing and hardcoded attempts

Motivation

This change enables browser-hosted Wasm containers to accept incoming connections on forwarded ports. Use cases include:

• Running web servers inside containers accessible from the host
• Port-based service discovery and access
• Multi-container networking scenarios

Technical Details

The implementation:

1. Container connects via WebSocket
2. c2w-net polls DHCP lease table to capture assigned IP
3. Port forwarders start with discovered IP as target
4. Falls back to default IP (192.168.127.3) after 10-second timeout

Testing

Existing integration tests continue to pass as changes only affect --listen-ws mode code path. The -p flag now works correctly with WebSocket mode.

tested on macos, android, ios.\

macos: works

android: looks like it works using screen logs, but dont have time rn to do a delegate
windows: no machine to test
ios: browser crashed

[ktock]

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