evy: Fix initial cursor position in SVG export

Fix initial cursor position in SVG export. We had it at `0 0` which is correct,
only that it wasn't transposed. Which means that the Evy program

	circle N

would render a circle at `0 100` instead of `0 0`.

pkg/cli/svg/runtime.go

@@ -72,6 +72,8 @@ func NewGraphicsRuntime() *GraphicsRuntime {
 			},
 		},
 	}
+	rt.x = rt.transformX(0)
+	rt.y = rt.transformY(0)
 	rt.Clear("white")
 	return rt
 }

pkg/cli/svg/runtime_test.go

@@ -19,10 +19,15 @@ func TestRuntimeCircleRect(t *testing.T) {
 	rt.Color("red")
 	rt.Circle(10)
 	rt.Gridn(10, "hsl(0deg 100% 0% / 50%)")
-
 	assertSVG(t, "testdata/circle-rect.svg", rt)
 }
 
+func TestRuntimeQuarterCircle(t *testing.T) {
+	rt := newTestRuntime()
+	rt.Circle(100) // should be centered at 0 0
+	assertSVG(t, "testdata/quarter-circle.svg", rt)
+}
+
 func TestRuntimeEllipse(t *testing.T) {
 	rt := newTestRuntime()
 	rt.Ellipse(50, 85, 30, 10, 0, 0, 0)