config: add OPTION_ENABLE_TCP_PUNCH

The client gains a switch for the TCP punch alongside the UDP, IPv6 and
WebRTC ones. Its "enable-" prefix gives it the usual default-on
semantics; unlike its siblings it is deliberately left out of the
self-hosted default-off list on the client side, since every hbbs has
always supported TCP punching.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016HV43uh1ztv6Wm5qi3Y1ne

src/config.rs

@@ -2993,6 +2993,7 @@ pub mod keys {
         "allow-command-line-settings-when-settings-disabled";
 
     // Connection punch-through options
+    pub const OPTION_ENABLE_TCP_PUNCH: &str = "enable-tcp-punch";
     pub const OPTION_ENABLE_UDP_PUNCH: &str = "enable-udp-punch";
     pub const OPTION_ENABLE_IPV6_PUNCH: &str = "enable-ipv6-punch";
     pub const OPTION_ENABLE_WEBRTC: &str = "enable-webrtc";
@@ -3126,6 +3127,7 @@ pub mod keys {
         OPTION_ALLOW_AUTO_RECORD_OUTGOING,
         OPTION_HIDE_RECORDING_BUTTON,
         OPTION_VIDEO_SAVE_DIRECTORY,
+        OPTION_ENABLE_TCP_PUNCH,
         OPTION_ENABLE_UDP_PUNCH,
         OPTION_ENABLE_IPV6_PUNCH,
         OPTION_ENABLE_WEBRTC,