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>

data/tree.go

@@ -25,7 +25,7 @@ type TreeOptions struct {
 }
 
 type TreeResult struct {
-	Element          *ui.Element
+	Element          ui.Element
 	Changed, Toggled bool
 }
 
@@ -55,7 +55,7 @@ func Tree(c *ui.Context, text string, roots []TreeNode, selected *string, o Tree
 	for i := range roots {
 		tops = append(tops, strconv.Itoa(i))
 	}
-	shell, base, st := pixel.Shell(c, func() *ui.Element {
+	shell, base, st := pixel.Shell(c, func() ui.Element {
 		return ui.Box(c).Focusable().Role(ui.RoleTree).Label(text).Disabled(o.Disabled)
 	})
 	opened := ui.Local(base, treeKey{}, func() map[string]bool { return map[string]bool{} })