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>

chart/legend.go

@@ -14,7 +14,7 @@ type LegendOptions struct {
 }
 
 type LegendResult struct {
-	Element *ui.Element
+	Element ui.Element
 	Changed bool
 }
 
@@ -29,7 +29,7 @@ func Legend(c *ui.Context, text string, series []Series, hidden []bool, o Legend
 	row.Children(func() {
 		for i, s := range series {
 			shown := !hidden[i]
-			shell, base, st := pixel.Shell(c, func() *ui.Element { return ui.ToggleBase(c, &shown).Label(s.Name).Disabled(o.Disabled) })
+			shell, base, st := pixel.Shell(c, func() ui.Element { return ui.ToggleBase(c, &shown).Label(s.Name).Disabled(o.Disabled) })
 			// The base turns before it learns it is off.
 			if base.Changed() && !base.IsDisabled() {
 				hidden[i], res.Changed = !shown, true