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>

input/slotpicker.go

@@ -14,7 +14,7 @@ type SlotPickerOptions struct {
 }
 
 type SlotPickerResult struct {
-	Element *ui.Element
+	Element ui.Element
 	Changed bool
 }
 
@@ -33,7 +33,7 @@ func SlotPicker(c *ui.Context, text string, value *int, options []string, o Slot
 	if *value < 0 || *value >= n {
 		panic(fmt.Sprintf("input: SlotPicker value %d outside %d options", *value, n))
 	}
-	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.RoleSlider).Label(text).Description(options[*value]).Disabled(o.Disabled)
 	})
 	s := ui.Local(base, reelKey{}, func() reel { return reel{} })