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/appframe.go

@@ -14,7 +14,7 @@ type AppFrameOptions struct {
 }
 
 // AppFrame arranges header, sidebar, main and footer; nil ones vanish.
-func AppFrame(c *ui.Context, o AppFrameOptions, header, sidebar, main, footer func()) *ui.Element {
+func AppFrame(c *ui.Context, o AppFrameOptions, header, sidebar, main, footer func()) ui.Element {
 	k := pixel.K(c)
 	sw := pixel.Or("AppFrame SidebarWidth", o.SidebarWidth, 96)
 	fold := pixel.Or("AppFrame FoldBelow", o.FoldBelow, 320)
@@ -43,7 +43,7 @@ func AppFrame(c *ui.Context, o AppFrameOptions, header, sidebar, main, footer fu
 		if header != nil {
 			strip(header, true)
 		}
-		var body *ui.Element
+		var body ui.Element
 		if folded {
 			body = ui.Column(c)
 		} else {