ipc, worker: dial and bind through netaddr (V-484)

Five hardcoded transports, three in internal/ipc and two in
internal/worker, all now go through the seam address. The unix perms
logic moved into netaddr, so the two copies of parentDir and the umask
dance are gone.

peerCaller already returned ok=false for a non-unix conn, so the
SO_PEERCRED path degrades correctly on tcp with no change.

internal/worker/client.go

@@ -24,6 +24,8 @@ import (
 	"net"
 	"sync"
 	"time"
+
+	"github.com/kami/maven/internal/netaddr"
 )
 
 // Client — one connection to one worker module. NOT goroutine-safe for
@@ -38,15 +40,25 @@ type Client struct {
 	dial func() (net.Conn, error)
 }
 
-// Dial opens a Client to the worker socket at path. The first call lazily
+// Dial opens a Client to the worker module at path. The first call lazily
 // dials; subsequent calls reuse the conn (a fresh dial happens on next call
 // after a teardown). Lazy dial keeps a worker that's restarting from
 // blocking core's startup; core attempts the dial on first use.
+//
+// path is a netaddr seam address. A bare path is the unix socket it has
+// always been; "tcp://workstation:9310?token=..." reaches a module on another
+// host, which is how stt and tts move to the machine with the GPU and the
+// microphone. A bad address surfaces on the first call, not here, because
+// Dial does not fail — see internal/netaddr.
 func Dial(path string) *Client {
+	addr, err := netaddr.Parse(path)
 	return &Client{
 		path: path,
 		dial: func() (net.Conn, error) {
-			return net.Dial("unix", path)
+			if err != nil {
+				return nil, err
+			}
+			return netaddr.Dial(addr)
 		},
 	}
 }