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>

display/display.go

@@ -10,7 +10,7 @@ import (
 )
 
 // art is a labeled w×h dot image that fn draws.
-func art(c *ui.Context, k pixel.Kit, label string, w, h int, fn func(g pixel.Canvas)) *ui.Element {
+func art(c *ui.Context, k pixel.Kit, label string, w, h int, fn func(g pixel.Canvas)) ui.Element {
 	e := ui.Box(c).Size(k.D(w), k.D(h))
 	if label != "" {
 		e.Label(label).Role(ui.RoleImage)