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/app/gl_ios.go

@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+//go:build darwin && ios && nometal
+
+package app
+
+/*
+@import UIKit;
+
+#include <CoreFoundation/CoreFoundation.h>
+#include <OpenGLES/ES2/gl.h>
+#include <OpenGLES/ES2/glext.h>
+
+__attribute__ ((visibility ("hidden"))) int gio_renderbufferStorage(CFTypeRef ctx, CFTypeRef layer, GLenum buffer);
+__attribute__ ((visibility ("hidden"))) int gio_presentRenderbuffer(CFTypeRef ctx, GLenum buffer);
+__attribute__ ((visibility ("hidden"))) int gio_makeCurrent(CFTypeRef ctx);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createContext(void);
+__attribute__ ((visibility ("hidden"))) CFTypeRef gio_createGLLayer(void);
+
+static CFTypeRef getViewLayer(CFTypeRef viewRef) {
+	@autoreleasepool {
+		UIView *view = (__bridge UIView *)viewRef;
+		return CFBridgingRetain(view.layer);
+	}
+}
+
+*/
+import "C"
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+
+	"gioui.org/gpu"
+	"gioui.org/internal/gl"
+)
+
+type context struct {
+	owner       *window
+	c           *gl.Functions
+	ctx         C.CFTypeRef
+	layer       C.CFTypeRef
+	init        bool
+	frameBuffer gl.Framebuffer
+	colorBuffer gl.Renderbuffer
+}
+
+func newContext(w *window) (*context, error) {
+	ctx := C.gio_createContext()
+	if ctx == 0 {
+		return nil, fmt.Errorf("failed to create EAGLContext")
+	}
+	api := contextAPI()
+	f, err := gl.NewFunctions(api.Context, api.ES)
+	if err != nil {
+		return nil, err
+	}
+	c := &context{
+		ctx:   ctx,
+		owner: w,
+		layer: C.getViewLayer(w.contextView()),
+		c:     f,
+	}
+	return c, nil
+}
+
+func contextAPI() gpu.OpenGL {
+	return gpu.OpenGL{}
+}
+
+func (c *context) RenderTarget() gpu.RenderTarget {
+	return gpu.OpenGLRenderTarget(c.frameBuffer)
+}
+
+func (c *context) API() gpu.API {
+	return contextAPI()
+}
+
+func (c *context) Release() {
+	if c.ctx == 0 {
+		return
+	}
+	C.gio_renderbufferStorage(c.ctx, 0, C.GLenum(gl.RENDERBUFFER))
+	c.c.DeleteFramebuffer(c.frameBuffer)
+	c.c.DeleteRenderbuffer(c.colorBuffer)
+	C.gio_makeCurrent(0)
+	C.CFRelease(c.ctx)
+	c.ctx = 0
+}
+
+func (c *context) Present() error {
+	if c.layer == 0 {
+		panic("context is not active")
+	}
+	c.c.BindRenderbuffer(gl.RENDERBUFFER, c.colorBuffer)
+	if C.gio_presentRenderbuffer(c.ctx, C.GLenum(gl.RENDERBUFFER)) == 0 {
+		return errors.New("presentRenderBuffer failed")
+	}
+	return nil
+}
+
+func (c *context) Lock() error {
+	// OpenGL contexts are implicit and thread-local. Lock the OS thread.
+	runtime.LockOSThread()
+
+	if C.gio_makeCurrent(c.ctx) == 0 {
+		return errors.New("[EAGLContext setCurrentContext] failed")
+	}
+	return nil
+}
+
+func (c *context) Unlock() {
+	C.gio_makeCurrent(0)
+}
+
+func (c *context) Refresh() error {
+	if C.gio_makeCurrent(c.ctx) == 0 {
+		return errors.New("[EAGLContext setCurrentContext] failed")
+	}
+	if !c.init {
+		c.init = true
+		c.frameBuffer = c.c.CreateFramebuffer()
+		c.colorBuffer = c.c.CreateRenderbuffer()
+	}
+	if !c.owner.visible {
+		// Make sure any in-flight GL commands are complete.
+		c.c.Finish()
+		return nil
+	}
+	currentRB := gl.Renderbuffer{uint(c.c.GetInteger(gl.RENDERBUFFER_BINDING))}
+	c.c.BindRenderbuffer(gl.RENDERBUFFER, c.colorBuffer)
+	if C.gio_renderbufferStorage(c.ctx, c.layer, C.GLenum(gl.RENDERBUFFER)) == 0 {
+		return errors.New("renderbufferStorage failed")
+	}
+	c.c.BindRenderbuffer(gl.RENDERBUFFER, currentRB)
+	c.c.BindFramebuffer(gl.FRAMEBUFFER, c.frameBuffer)
+	c.c.FramebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, c.colorBuffer)
+	if st := c.c.CheckFramebufferStatus(gl.FRAMEBUFFER); st != gl.FRAMEBUFFER_COMPLETE {
+		return fmt.Errorf("framebuffer incomplete, status: %#x\n", st)
+	}
+	return nil
+}
+
+func (w *window) NewContext() (Context, error) {
+	return newContext(w)
+}