fix(ios): one address picker for every bring-up

bringUpRunner reads the picker from a field, and NewDevice only ever set
the device one, so a device driver that reached bringUpRunner would call
nil. The two fields held the same function; keeping one leaves no path
that can be wired without it.

internal/driver/ioscompanion/device.go

@@ -103,9 +103,9 @@ func NewDevice(ctx context.Context, options DeviceOptions) (*Driver, error) {
 		}
 	}
 	if options.pickAddress != nil {
-		d.pickDeviceAddress = options.pickAddress
+		d.pickRunnerAddress = options.pickAddress
 	} else {
-		d.pickDeviceAddress = pickLoopbackAddress
+		d.pickRunnerAddress = pickLoopbackAddress
 	}
 
 	// Device seams: clear-state reinstalls via devicectl; the container reset and
@@ -159,7 +159,7 @@ func NewDevice(ctx context.Context, options DeviceOptions) (*Driver, error) {
 // health. The build runs inside spawnRunner under the process context, so the
 // startup timeout only bounds the post-spawn wait, not the build.
 func (d *Driver) bringUpDevice(ctx context.Context) error {
-	address, err := d.pickDeviceAddress()
+	address, err := d.pickRunnerAddress()
 	if err != nil {
 		return err
 	}

internal/driver/ioscompanion/driver.go

@@ -162,9 +162,13 @@ type Driver struct {
 	runnerAddress string
 	spawnRunner   func(ctx context.Context, address string) (*exec.Cmd, error)
 	dialRunner    func(address string) (transport.Companion, error)
-	pickRunnerAddress func() (string, error)
 	hybrid        bool
 
+	// pickRunnerAddress hands every bring-up a free loopback port, on the
+	// simulator and the device alike. One field, so no path can be wired
+	// without it.
+	pickRunnerAddress func() (string, error)
+
 	// Device-mode fields. On the physical-device path d.companion is the runner
 	// dialed over a usbmux tunnel, hybrid is false, and runnerClient is nil.
 	// coreDeviceID feeds devicectl; tunnel is the in-process usbmux forwarder
@@ -173,7 +177,6 @@ type Driver struct {
 	coreDeviceID string
 	tunnel       io.Closer
 	startTunnel  func(ctx context.Context, hardwareUDID, localAddress, devicePort string) (io.Closer, error)
-	pickDeviceAddress func() (string, error)
 
 	// processContext owns the companion child's lifetime: it is derived from
 	// New's context (so a canceled run still reaps the child) and canceled by