fix: skip TestHostnameByPid when setns is not permitted

setns(2) requires CAP_SYS_ADMIN. Probe with self PID before running
the test cases and skip the whole test when EPERM is returned, so the
suite passes in unprivileged environments such as OrbStack on
Apple Silicon.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: hao022

internal/utils/executil/exec_test.go

@@ -16,10 +16,12 @@ package executil
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
 	"runtime"
+	"syscall"
 	"testing"
 
 	"huatuo-bamai/internal/procfs"
@@ -132,6 +134,11 @@ func TestHostnameByPid(t *testing.T) {
 
 	selfPid := uint32(os.Getpid())
 
+	// setns(2) requires CAP_SYS_ADMIN; skip the whole test in unprivileged environments.
+	if _, err := HostnameByPid(selfPid); errors.Is(err, syscall.EPERM) {
+		t.Skip("setns requires CAP_SYS_ADMIN; skipping in unprivileged environment")
+	}
+
 	tests := []struct {
 		name     string
 		pid      uint32