Fix SOCKS proxy hangs and enable third-party resource loading

[Pebl3]

Disclaimer... all code is completely AI generated, but I have verified that the patch works and removed bloat.

Summary

Two bugs made the SOCKS proxy unusable for real browser traffic against relayed targets: non-relay hosts (CDNs, fonts) got rejected outright, and a single slow relay response could deadlock the entire proxy. This PR fixes both.

Problems

1. Third-party resources rejected. The SOCKS handler required every connection to have an active relay session, so any page pulling in CDN/font assets failed:

[-] SOCKS: Don't have a relay for cdn.jsdelivr.net(443)
[-] SOCKS: Don't have a relay for fonts.googleapis.com(443)

2. Whole-proxy deadlock after a few seconds. The relay socket used settimeout(None), and every recv() path (transferResponse body read, transferChunked) was unguarded. One slow/hung response from the target held socketLock forever. Every subsequent browser connection blocked on lock acquisition and the browser spun on "infinite loading."

Changes

lib/relay/servers/socksserver.py — direct TCP passthrough for non-relay traffic

• Removed the early CONNECTION_REFUSED gate for unknown hosts.
• Added a select-based bidirectional pipe in the "no relay handler" branch, matching the pattern already used for DNS (port 53).
• Relay targets still go through the NTLM plugin path unchanged.

lib/relay/servers/socksplugins/http.py — bounded relay I/O

• New _sendViaRelay() helper wrapping the lock/send/recv sequence:
  • 15s lock acquire timeout → 503 to browser (session preserved).
  • 10s socket-level timeout on relaySocket covers every recv() in transferResponse and transferChunked.
  • On timeout/socket error → 504 to browser, close the relay socket so later handlers fail isConnectionAlive() cleanly instead of reading misaligned response bytes.
• Collapsed 5 duplicated with socketLock: blocks in _processRequestWithProbe into single _sendViaRelay() calls.

Behavior

Scenario	Before	After
Browser request to CDN / fonts / any non-relay host	CONNECTION_REFUSED	Direct TCP passthrough
Relay target, fast response	Works	Works
Relay target, target hangs >10s	Whole proxy deadlocks until restart	504 to that browser, session killed, proxy stays responsive
Concurrent browser connections contending on relay socket	Serialized (pre-existing)	Serialized with 15s cap, fail-fast with 503 on excess contention

Trade-offs

A true target-side hang now ends the NTLM session (relay socket closed). Re-capture is needed — acceptable since the alternative is a dead proxy.