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>

code/pixeleditor.go

@@ -27,7 +27,7 @@ type PixelEditorOptions struct {
 }
 
 type PixelEditorResult struct {
-	Element *ui.Element
+	Element ui.Element
 	// Changed is the art; Copied is COPY.
 	Changed, Copied bool
 }
@@ -129,7 +129,7 @@ func PixelEditor(c *ui.Context, text string, art *string, o PixelEditorOptions)
 }
 
 // canvas paints cells, checkers where clear, grid and cursor.
-func canvas(shell *ui.Element, k pixel.Kit, st pixel.State, cells []int, w, z, cur int, grid bool) {
+func canvas(shell ui.Element, k pixel.Kit, st pixel.State, cells []int, w, z, cur int, grid bool) {
 	shell.Draw(func(p *ui.Painter, r ui.Rect) {
 		g := k.Canvas(p, r)
 		for i, v := range cells {