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>

layout/titlebar.go

@@ -32,7 +32,7 @@ type TitleBarOptions struct {
 }
 
 type TitleBarResult struct {
-	Element  *ui.Element
+	Element  ui.Element
 	Close    bool
 	Minimize bool
 }
@@ -67,7 +67,7 @@ func TitleBar(c *ui.Context, title string, o TitleBarOptions) TitleBarResult {
 
 // windowBox is a framed button showing its glyph on hover.
 func windowBox(c *ui.Context, k pixel.Kit, glyph *pixel.Sprite, name string, disabled bool) bool {
-	shell, base, st := pixel.Shell(c, func() *ui.Element { return ui.ButtonBase(c).Label(name).Disabled(disabled) })
+	shell, base, st := pixel.Shell(c, func() ui.Element { return ui.ButtonBase(c).Label(name).Disabled(disabled) })
 	shell.Size(k.D(11), k.D(11)).Draw(func(p *ui.Painter, r ui.Rect) {
 		g := k.Canvas(p, r)
 		fill := pixel.Face