chore(v2): vendor dependencies for offline/China builds

go mod vendor pins onnxruntime_go v1.12.1, Gio and the rest into v2/vendor
so go run/build work without hitting proxy.golang.org (blocked/slow in
China). Verified: CGO_ENABLED=1 go build -mod=vendor ./internal/spike and
GOOS=windows go build -mod=vendor ./internal/ui both pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

v2/vendor/gioui.org/widget/material/radiobutton.go

@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package material
+
+import (
+	"gioui.org/io/semantic"
+	"gioui.org/layout"
+	"gioui.org/widget"
+)
+
+type RadioButtonStyle struct {
+	checkable
+	Key   string
+	Group *widget.Enum
+}
+
+// RadioButton returns a RadioButton with a label. The key specifies
+// the value for the Enum.
+func RadioButton(th *Theme, group *widget.Enum, key, label string) RadioButtonStyle {
+	r := RadioButtonStyle{
+		Group: group,
+		checkable: checkable{
+			Label: label,
+
+			Color:              th.Palette.Fg,
+			IconColor:          th.Palette.ContrastBg,
+			TextSize:           th.TextSize * 14.0 / 16.0,
+			Size:               26,
+			shaper:             th.Shaper,
+			checkedStateIcon:   th.Icon.RadioChecked,
+			uncheckedStateIcon: th.Icon.RadioUnchecked,
+		},
+		Key: key,
+	}
+	r.checkable.Font.Typeface = th.Face
+	return r
+}
+
+// Layout updates enum and displays the radio button.
+func (r RadioButtonStyle) Layout(gtx layout.Context) layout.Dimensions {
+	r.Group.Update(gtx)
+	hovered, hovering := r.Group.Hovered()
+	focus, focused := r.Group.Focused()
+	return r.Group.Layout(gtx, r.Key, func(gtx layout.Context) layout.Dimensions {
+		semantic.RadioButton.Add(gtx.Ops)
+		highlight := hovering && hovered == r.Key || focused && focus == r.Key
+		return r.layout(gtx, r.Group.Value == r.Key, highlight)
+	})
+}