Upgrade MyGo to v0.5.5

Elements are now pass-scoped value handles: tests that read bounds
after a frame bind a ui.Handle. pixel tells frames apart by the build
pass's root, since the Tester clock no longer moves on its own.

Fix the regressions the upgrade brought:
- Clipboard reads in input handlers go through c.Services().
- MyGo notes an overlay's opener after building it, so AutoFocus
  inside lost it; pixel.AutoFocus focuses through a Handle, and
  archtest bans the raw call. Dialogs hand the focus back again.
- Elements around a press stay hovered: Tooltip tells a press-given
  focus by focus arriving under the pointer.
- The web host moves the Tester clock with real time, at most 500 ms
  a call, and gives components the real clock.

The gallery's source index also accepts CRLF checkouts.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

input/buttongroup.go

@@ -17,7 +17,7 @@ type ButtonGroupOptions struct {
 }
 
 type ButtonGroupResult struct {
-	Element *ui.Element
+	Element ui.Element
 	// Clicked is the button clicked this frame, or -1.
 	Clicked int
 }
@@ -29,7 +29,7 @@ func ButtonGroup(c *ui.Context, labels []string, o ButtonGroupOptions) ButtonGro
 	res := ButtonGroupResult{Clicked: -1}
 	res.Element = ui.Row(c).Role(ui.RoleToolbar).Label(o.Label).FocusGroup(ui.Horizontal).Children(func() {
 		for i, l := range labels {
-			shell, base, st := pixel.Shell(c, func() *ui.Element { return ui.ButtonBase(c).Label(l).Disabled(o.Disabled) })
+			shell, base, st := pixel.Shell(c, func() ui.Element { return ui.ButtonBase(c).Label(l).Disabled(o.Disabled) })
 			w := pixel.Measure(l)*sc + 2*pad
 			if i > 0 {
 				shell.Margin(0, 0, 0, k.D(-1))