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/clocks_test.go

@@ -169,7 +169,7 @@ func TestRelativeTimeAsksForTheNextMinute(t *testing.T) {
 	at := clk.t.Add(-90 * time.Second)
 	tt := view(300, 60, clk, false, func(c *ui.Context) { datetime.RelativeTime(c, at, datetime.RelativeTimeOptions{}) })
 	pixel.ResetDue()
-	before := time.Now()
+	before := tt.Now()
 	tt.Frame()
 	// The words change at two minutes: thirty seconds on.
 	if wait := pixel.Due().Sub(before); wait < 29*time.Second || wait > 31*time.Second {