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>

overlay/sheet.go

@@ -15,7 +15,7 @@ type SheetOptions struct {
 }
 
 type SheetResult struct {
-	Element *ui.Element
+	Element ui.Element
 	// Closed is a drag down, Escape or a click outside.
 	Closed bool
 }
@@ -32,7 +32,7 @@ func Sheet(c *ui.Context, text string, open *bool, o SheetOptions, content func(
 	rise := k.D(arriving(c, home, *open) * h / 4)
 	was := *open
 	var res SheetResult
-	res.Element = ui.DialogBase(c, open, func(back, panel *ui.Element) {
+	res.Element = ui.DialogBase(c, open, func(back, panel ui.Element) {
 		dim(k, back, pixel.Back, 8)
 		panel.Label(text).Focusable().FocusRing(false).Draw(func(p *ui.Painter, r ui.Rect) {
 			g := k.Canvas(p, r)