Fix IPv6 TCP tunnel display formatting (#1980)

Normalize composite tunnel display values before rendering peer and
debug output so IPv6 tunnel types no longer append `6` to the port.

- Preserve prefixes like `txt-` while converting tunnel schemes to
  their IPv6 form.
- Recover malformed values such as `txt-tcp://...:110106` into
  `txt-tcp6://...:11010`.
- Reuse the normalized remote address display in CLI debug output.

easytier/src/connector/dns_connector.rs

@@ -194,11 +194,11 @@ impl super::TunnelConnector for DnsTunnelConnector {
             TunnelInfo {
                 local_addr: info.local_addr.clone(),
                 remote_addr: Some(self.addr.clone().into()),
-                tunnel_type: format!(
-                    "{}-{}",
-                    self.addr.scheme(),
-                    info.remote_addr.unwrap_or_default()
-                ),
+                resolved_remote_addr: info
+                    .resolved_remote_addr
+                    .clone()
+                    .or(info.remote_addr.clone()),
+                tunnel_type: format!("{}-{}", self.addr.scheme(), info.tunnel_type),
             },
         )))
     }