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/GioActivity.java

@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: Unlicense OR MIT
+
+package org.gioui;
+
+import android.app.Activity;
+import android.os.Bundle;
+import android.content.Intent;
+import android.content.res.Configuration;
+import android.view.ViewGroup;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.FrameLayout;
+
+public final class GioActivity extends Activity {
+	private GioView view;
+	public FrameLayout layer;
+
+	@Override public void onCreate(Bundle state) {
+            super.onCreate(state);
+
+            layer = new FrameLayout(this);
+            view = new GioView(this);
+
+            view.setLayoutParams(new FrameLayout.LayoutParams(
+                FrameLayout.LayoutParams.MATCH_PARENT,
+                FrameLayout.LayoutParams.MATCH_PARENT
+            ));
+            view.setFocusable(true);
+            view.setFocusableInTouchMode(true);
+
+            layer.addView(view);
+            setContentView(layer);
+            onNewIntent(this.getIntent());
+	}
+
+	@Override public void onDestroy() {
+		view.destroy();
+		super.onDestroy();
+	}
+
+	@Override public void onStart() {
+		super.onStart();
+		view.start();
+	}
+
+	@Override public void onStop() {
+		view.stop();
+		super.onStop();
+	}
+
+	@Override public void onPause() {
+        super.onPause();
+        view.pause();
+	}
+
+	@Override public void onResume() {
+        super.onResume();
+        view.resume();
+	}
+
+	@Override public void onConfigurationChanged(Configuration c) {
+		super.onConfigurationChanged(c);
+		view.configurationChanged();
+	}
+
+	@Override public void onLowMemory() {
+		super.onLowMemory();
+		GioView.onLowMemory();
+	}
+
+	@Override public void onBackPressed() {
+		if (!view.backPressed())
+			super.onBackPressed();
+	}
+
+	@Override protected void onNewIntent(Intent intent) {
+		super.onNewIntent(intent);
+		view.onIntentEvent(intent);
+	}
+}