R-861: narrow the agent's root grants — exact sudo patterns, felhom-priv-apply content checker, fixed hook/parent files in the bundle, signed self-update verified as root, escrow root reads pinned

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0159rPz1ZhFKsS53msqPYxtS

internal/privapplytest/check.go

@@ -0,0 +1,34 @@
+// Package privapplytest runs configs/felhom-priv-apply in CHECK-ONLY mode from Go tests (R-861): each renderer's
+// real output must be accepted by the root checker, so the two can never drift apart unnoticed. Test-only helper.
+package privapplytest
+
+import (
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"testing"
+)
+
+// Check writes content to a temp file and runs `felhom-priv-apply --check <verb> [name] <file>`. It returns the
+// checker's verdict line ("OK" or "REFUSED [rule] …"). Skips when python3 is absent.
+func Check(t *testing.T, verb, name, content string) string {
+	t.Helper()
+	py, err := exec.LookPath("python3")
+	if err != nil {
+		t.Skip("python3 not available")
+	}
+	_, here, _, _ := runtime.Caller(0)
+	wrapper := filepath.Join(filepath.Dir(here), "..", "..", "configs", "felhom-priv-apply")
+	f := filepath.Join(t.TempDir(), "staged")
+	if err := os.WriteFile(f, []byte(content), 0o600); err != nil {
+		t.Fatal(err)
+	}
+	args := []string{"-B", wrapper, "--check", verb}
+	if name != "" {
+		args = append(args, name)
+	}
+	out, _ := exec.Command(py, append(args, f)...).CombinedOutput()
+	return strings.TrimSpace(string(out))
+}