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/progresscircle.go

@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package material
+
+import (
+	"image"
+	"image/color"
+	"math"
+
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/paint"
+)
+
+type ProgressCircleStyle struct {
+	Color    color.NRGBA
+	Progress float32
+}
+
+func ProgressCircle(th *Theme, progress float32) ProgressCircleStyle {
+	return ProgressCircleStyle{
+		Color:    th.Palette.ContrastBg,
+		Progress: progress,
+	}
+}
+
+func (p ProgressCircleStyle) Layout(gtx layout.Context) layout.Dimensions {
+	diam := gtx.Constraints.Min.X
+	if minY := gtx.Constraints.Min.Y; minY > diam {
+		diam = minY
+	}
+	if diam == 0 {
+		diam = gtx.Dp(24)
+	}
+	sz := gtx.Constraints.Constrain(image.Pt(diam, diam))
+	radius := sz.X / 2
+	defer op.Offset(image.Pt(radius, radius)).Push(gtx.Ops).Pop()
+
+	defer clipLoader(gtx.Ops, -math.Pi/2, -math.Pi/2+math.Pi*2*p.Progress, float32(radius)).Push(gtx.Ops).Pop()
+	paint.ColorOp{
+		Color: p.Color,
+	}.Add(gtx.Ops)
+	paint.PaintOp{}.Add(gtx.Ops)
+	return layout.Dimensions{
+		Size: sz,
+	}
+}