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/chat_test.go

@@ -262,7 +262,7 @@ func TestDateSeparatorNamesTheDay(t *testing.T) {
 	day := wd.clk.t
 	pixel.ResetDue()
 	tt := view(400, 100, wd, func(c *ui.Context) { chat.DateSeparator(c, day, chat.DateSeparatorOptions{}) })
-	if until := time.Until(pixel.Due()); until <= 0 || until > 2*time.Second {
+	if until := pixel.Due().Sub(tt.Now()); until <= 0 || until > 2*time.Second {
 		t.Fatalf("the next build is due in %v, not at midnight", until)
 	}
 	wd.clk.t = wd.clk.t.Add(2 * time.Second)