feat(v2): complete Go inference and UI spike

v2/internal/spike/ort_test.go

@@ -0,0 +1,16 @@
+package spike
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestRunPoseRejectsWrongInputLengthBeforeLoadingRuntime(t *testing.T) {
+	_, err := RunPose("missing.onnx", "missing.dll", []float32{0})
+	if err == nil {
+		t.Fatal("RunPose accepted an input that is not 1x3x640x640")
+	}
+	if !strings.Contains(err.Error(), "input length") {
+		t.Fatalf("RunPose error = %q, want input length error", err)
+	}
+}