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>

feedback/busyoverlay.go

@@ -11,7 +11,7 @@ type BusyOverlayOptions struct{}
 type busyKey struct{}
 
 // BusyOverlay veils busy content, whose controls then take no input.
-func BusyOverlay(c *ui.Context, busy bool, o BusyOverlayOptions, content func()) *ui.Element {
+func BusyOverlay(c *ui.Context, busy bool, o BusyOverlayOptions, content func()) ui.Element {
 	k := pixel.K(c)
 	outer := ui.Box(c)
 	// held is whether the veil had the focus last frame.
@@ -29,7 +29,7 @@ func BusyOverlay(c *ui.Context, busy bool, o BusyOverlayOptions, content func())
 		s := pixel.Current(c)
 		s.Inert = s.Inert || busy
 		before := c.Root().Focused()
-		var body *ui.Element
+		var body ui.Element
 		pixel.Scope(c, s, func() { body = ui.Box(c).Children(content) })
 		if !busy {
 			return