test: sample padding pixel so movestate colors survive Linux fonts

x=20 sits on a digit glyph with CI's Linux fonts, so the assert compared
an antialiased glyph blend against the pure background. The padding area
(border 1px + padding 6px) can never contain text on any font.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0147jE48bQUTm9AqNQApT6b2

tests/unit/gui/test_motor_move_group.py

@@ -120,8 +120,12 @@ def test_spin_move_state_colors_actually_render(qtbot):
     spin.show()
 
     def value_area_color():
+        # Sample inside the left padding (1px border + 6px QSS padding), not
+        # the text area: glyph positions are font-dependent and on CI's Linux
+        # fonts x=20 lands on a digit of "12.40", returning an antialiased
+        # glyph/background blend instead of the plain background color.
         img = spin.grab().toImage()
-        return img.pixelColor(20, img.height() // 2)
+        return img.pixelColor(4, img.height() // 2)
 
     state.update_actual(12.0)
     neutral = value_area_color()