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>

navigation/documenttabs.go

@@ -22,7 +22,7 @@ type DocumentTabsOptions struct {
 }
 
 type DocumentTabsResult struct {
-	Element *ui.Element
+	Element ui.Element
 	Changed bool
 	// Closed is the tab × or Delete closed, or -1.
 	Closed int
@@ -46,8 +46,8 @@ func DocumentTabs(c *ui.Context, text string, titles []string, selected *int, o
 		for i, t := range titles {
 			// Keyed by title, so focus follows its tab.
 			ui.Box(c).Key(t).Children(func() {
-				var x *ui.Element
-				shell, base, st := pixel.Shell(c, func() *ui.Element {
+				var x ui.Element
+				shell, base, st := pixel.Shell(c, func() ui.Element {
 					tab := p.Tab(i).Label(t).Disabled(o.Disabled)
 					// The × is no Tab stop; Delete closes by keyboard.
 					tab.Children(func() {