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/views_test.go

@@ -238,7 +238,7 @@ func TestTodayMarksMoveAtMidnight(t *testing.T) {
 	} {
 		tt := view(600, 400, clk, false, build)
 		pixel.ResetDue()
-		before := time.Now()
+		before := tt.Now()
 		tt.Frame()
 		if due := pixel.Due(); due.IsZero() || due.Sub(before) > 2*time.Second {
 			t.Fatalf("%s: no rebuild asked for midnight, due %v", name, due)
@@ -264,7 +264,7 @@ func TestRelativeTimeRoundsTheFutureUp(t *testing.T) {
 		at := clk.t.Add(tc.ahead)
 		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()
 		if wait := pixel.Due().Sub(before); !shows(tt, tc.words) || wait < tc.wait-time.Second || wait > tc.wait+time.Second {
 			t.Fatalf("%v ahead: %q, next repaint in %v", tc.ahead, tt.Texts(), wait)