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>

layout/scrollarea.go

@@ -32,7 +32,7 @@ type ScrollAreaOptions struct {
 }
 
 type ScrollAreaResult struct {
-	Element *ui.Element
+	Element ui.Element
 	// Changed reports the view moved since the last frame.
 	Changed bool
 }
@@ -66,7 +66,7 @@ func ScrollArea(c *ui.Context, s *ui.ScrollState, o ScrollAreaOptions, children
 		}
 		st.end = s.MaxY
 	}
-	var v *ui.Element
+	var v ui.Element
 	row.Children(func() {
 		scrollBar(c, k, s, view, o.Disabled || inert, o.Disabled)
 		// A disabled view is a new element; the focus leaves.
@@ -161,7 +161,7 @@ func thumb(h, view, y, maxY, dot float32) (size, at float32) {
 
 // arrow is a scrollbar button; keys scroll the view instead.
 func arrow(c *ui.Context, k pixel.Kit, sp *pixel.Sprite, label string, disabled bool) bool {
-	shell, base, st := pixel.Shell(c, func() *ui.Element {
+	shell, base, st := pixel.Shell(c, func() ui.Element {
 		return ui.Box(c).Role(ui.RoleButton).Label(label).Disabled(disabled)
 	})
 	shell.Size(k.D(barW), k.D(barW)).Draw(func(p *ui.Painter, r ui.Rect) {