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/segmented.go

@@ -13,7 +13,7 @@ type SegmentedOptions struct {
 }
 
 type SegmentedResult struct {
-	Element *ui.Element
+	Element ui.Element
 	Changed bool
 }
 
@@ -32,7 +32,7 @@ func Segmented(c *ui.Context, text string, labels []string, selected *int, o Seg
 		g.Frame(0, 0, g.W, g.H, pixel.Notched, pixel.Face)
 	}).Children(func() {
 		for i, l := range labels {
-			shell, _, st := pixel.Shell(c, func() *ui.Element { return p.Segment(i).Label(l).Disabled(o.Disabled) })
+			shell, _, st := pixel.Shell(c, func() ui.Element { return p.Segment(i).Label(l).Disabled(o.Disabled) })
 			shell.Size(k.D(pixel.Measure(l)+12), k.D(pixel.LineHeight+4)).Draw(func(pt *ui.Painter, r ui.Rect) {
 				g := k.Canvas(pt, r)
 				ink := pixel.Ink