feat(cli): add config settings registry

internal/cli/config_registry_test.go

@@ -0,0 +1,28 @@
+package cli
+
+import "testing"
+
+func TestSettingsRegistry(t *testing.T) {
+	def, ok := settingsRegistry["audit_retention_days"]
+	if !ok {
+		t.Fatal("audit_retention_days must be registered")
+	}
+	if def.desc == "" {
+		t.Error("registered setting needs a description")
+	}
+	if err := def.validate("30"); err != nil {
+		t.Errorf("validate(30) = %v, want nil", err)
+	}
+	for _, bad := range []string{"-1", "abc", ""} {
+		if def.validate(bad) == nil {
+			t.Errorf("validate(%q) = nil, want error", bad)
+		}
+	}
+	if _, ok := settingsRegistry["nope"]; ok {
+		t.Error("unknown key must not be present")
+	}
+	keys := settingKeys()
+	if len(keys) != len(settingsRegistry) {
+		t.Fatalf("settingKeys len=%d, want %d", len(keys), len(settingsRegistry))
+	}
+}