v0.3.1: IP-literal destinations -> plain TCP passthrough (always)

User reported log spam on Windows with many 'relay failed: خطای SSL'
errors for IP-literal targets like 172.105.237.214:443. Root cause:
xray/VLESS, torrent, SSH, and other app-level clients use raw IPs in
CONNECT/SOCKS5 targets. Our previous logic would MITM these, see
'POST /' inside the xhttp wrapping, forward to Apps Script, which
would then fail SSL-verifying the app's self-signed backend.

New heuristic: if the CONNECT target is an IP literal, skip MITM
entirely and do plain TCP passthrough. Reasoning: browsers never
use raw IPs in CONNECT -- they always have a domain. Any client
using an IP literal is using a custom protocol that we have no
business MITMing.

Effect: xray/VLESS tunnels now work through mhrv-rs SOCKS5 (the
app's own TLS wrap passes through untouched). Browser HTTPS still
MITM'd + relayed as before (domain CONNECTs).

Also downgraded 'relay failed' logs from error to warn so they don't
spam the ERROR channel on misrouted traffic.

Cargo.lock

@@ -365,7 +365,7 @@ checksum = "f8ca58f447f06ed17d5fc4043ce1b10dd205e060fb3ce5b979b8ed8e59ff3f79"
 
 [[package]]
 name = "mhrv-rs"
-version = "0.3.0"
+version = "0.3.1"
 dependencies = [
  "base64",
  "bytes",