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/gpu/timer.go

@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package gpu
+
+import (
+	"time"
+
+	"gioui.org/gpu/internal/driver"
+)
+
+type timers struct {
+	backend driver.Device
+	timers  []*timer
+}
+
+type timer struct {
+	Elapsed time.Duration
+	backend driver.Device
+	timer   driver.Timer
+	state   timerState
+}
+
+type timerState uint8
+
+const (
+	timerIdle timerState = iota
+	timerRunning
+	timerWaiting
+)
+
+func newTimers(b driver.Device) *timers {
+	return &timers{
+		backend: b,
+	}
+}
+
+func (t *timers) newTimer() *timer {
+	if t == nil {
+		return nil
+	}
+	tt := &timer{
+		backend: t.backend,
+		timer:   t.backend.NewTimer(),
+	}
+	t.timers = append(t.timers, tt)
+	return tt
+}
+
+func (t *timer) begin() {
+	if t == nil || t.state != timerIdle {
+		return
+	}
+	t.timer.Begin()
+	t.state = timerRunning
+}
+
+func (t *timer) end() {
+	if t == nil || t.state != timerRunning {
+		return
+	}
+	t.timer.End()
+	t.state = timerWaiting
+}
+
+func (t *timers) ready() bool {
+	if t == nil {
+		return false
+	}
+	for _, tt := range t.timers {
+		switch tt.state {
+		case timerIdle:
+			continue
+		case timerRunning:
+			return false
+		}
+		d, ok := tt.timer.Duration()
+		if !ok {
+			return false
+		}
+		tt.state = timerIdle
+		tt.Elapsed = d
+	}
+	return t.backend.IsTimeContinuous()
+}
+
+func (t *timers) Release() {
+	if t == nil {
+		return
+	}
+	for _, tt := range t.timers {
+		tt.timer.Release()
+	}
+	t.timers = nil
+}