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>

chat/poll.go

@@ -23,7 +23,7 @@ type PollOptions struct {
 }
 
 type PollResult struct {
-	Element *ui.Element
+	Element ui.Element
 	// Voted is the option voted for this frame, else -1.
 	Voted int
 }
@@ -65,7 +65,7 @@ func Poll(c *ui.Context, question string, opts []PollOption, mine *int, o PollOp
 // bar fills an option's share; ▶ marks your vote.
 func bar(c *ui.Context, k pixel.Kit, op PollOption, total int, mine bool, w int, disabled bool) bool {
 	label := fmt.Sprintf("%s, %d", op.Text, op.Votes)
-	shell, base, st := pixel.Shell(c, func() *ui.Element {
+	shell, base, st := pixel.Shell(c, func() ui.Element {
 		return ui.ButtonBase(c).Label(label).Disabled(disabled).FocusRing(false)
 	})
 	n := strconv.Itoa(op.Votes)