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>

datetime/dateinput.go

@@ -15,7 +15,7 @@ type DateInputOptions struct {
 }
 
 type DateInputResult struct {
-	Element *ui.Element
+	Element ui.Element
 	Changed bool
 }
 
@@ -28,7 +28,7 @@ type popping struct{ open, held bool }
 func DateInput(c *ui.Context, text string, date *time.Time, o DateInputOptions) DateInputResult {
 	k := pixel.K(c)
 	old := *date
-	shell, base, st := pixel.Shell(c, func() *ui.Element {
+	shell, base, st := pixel.Shell(c, func() ui.Element {
 		return ui.ButtonBase(c).Role(ui.RolePopUpButton).Label(text).Disabled(o.Disabled)
 	})
 	pop := ui.Local(base, dateKey{}, func() popping { return popping{} })
@@ -53,7 +53,7 @@ func DateInput(c *ui.Context, text string, date *time.Time, o DateInputOptions)
 		g.Sprite(g.W-icon.Calendar.W-4, (g.H-icon.Calendar.H)/2, icon.Calendar, 0, pixel.Faint, 1)
 		g.Finish(st)
 	})
-	ui.PopoverBase(c, base, open, func(panel *ui.Element) {
+	ui.PopoverBase(c, base, open, func(panel ui.Element) {
 		panel.Padding(k.D(5)).Draw(func(p *ui.Painter, r ui.Rect) {
 			g := k.Canvas(p, r)
 			g.Frame(0, 0, g.W, g.H, pixel.Window, pixel.Face)