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>

feedback/spinner.go

@@ -15,7 +15,7 @@ type SpinnerOptions struct {
 var ring = [8][2]int{{5, 1}, {8, 2}, {9, 5}, {8, 8}, {5, 9}, {2, 8}, {1, 5}, {2, 2}}
 
 // Spinner turns through eight frames, even under Reduce Motion.
-func Spinner(c *ui.Context, text string, o SpinnerOptions) *ui.Element {
+func Spinner(c *ui.Context, text string, o SpinnerOptions) ui.Element {
 	k := pixel.K(c)
 	s := pixel.Or("Spinner Scale", o.Scale, 1)
 	if s > 4 {