Make aggregate ONNX gates execute for real

Reference-count the process-global ONNX Runtime across embedder and routing-head sessions, make close idempotent, and require named proof that both aggregate routing gates executed rather than self-skipped (V-716). Owner explicitly requested direct commits to master.

cmd/mavend/onnx_testmain_test.go

@@ -0,0 +1,36 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"testing"
+
+	"github.com/kami/maven/internal/router"
+)
+
+// TestMain holds one ONNX Runtime lease across the model-aware topic and
+// personal-boundary gates. Each test still owns and closes its model session;
+// the process-global environment is released only after the final test.
+func TestMain(m *testing.M) {
+	var lease *router.ONNXRuntimeLease
+	lib := os.Getenv("MAVEN_ONNX_LIB")
+	if lib != "" {
+		if _, err := os.Stat(lib); err == nil {
+			var acquireErr error
+			lease, acquireErr = router.AcquireONNXRuntime(lib)
+			if acquireErr != nil {
+				fmt.Fprintf(os.Stderr, "initialize shared ONNX test runtime: %v\n", acquireErr)
+				os.Exit(2)
+			}
+		}
+	}
+
+	code := m.Run()
+	if lease != nil {
+		if err := lease.Close(); err != nil {
+			fmt.Fprintf(os.Stderr, "ONNX test runtime cleanup: %v\n", err)
+			code = 1
+		}
+	}
+	os.Exit(code)
+}