This type seems to be a migration shim for TCP tailscaled sockets
(instead of unix/windows pipes). The `port` field was never set, so it
was effectively used as a string (`path` field).
Remove the whole type and simplify call sites to pass the socket path
directly to `safesocket.Connect`.
Updates #cleanup
Signed-off-by: Andrew Lytvynov <awly@tailscale.com>