Fix service methods descriptor lookup and telephony example flags

- service methods: fall back to knownServiceNames reverse lookup when
  InterfaceTransaction returns empty descriptor (framework services)
- Fix telephony get-network-country-iso-for-phone: only --phoneId flag
  exists (no --callingPackage/--callingFeatureId in generated code)
- Update README and E2E test to match actual flag names

Author: xaionaro@dx.center

README.md

@@ -1438,7 +1438,7 @@ aidlcli com.android.internal.telephony.ITelephony get-active-phone-type
 
 # Get network country ISO
 aidlcli com.android.internal.telephony.ITelephony get-network-country-iso-for-phone \
-  --phoneId 0 --callingPackage com.android.shell --callingFeatureId ""
+  --phoneId 0
 ```
 
 </details>

cmd/aidlcli/cmd_service.go

@@ -224,20 +224,33 @@ func newServiceMethodsCmd() *cobra.Command {
 
 			descriptor := queryDescriptor(ctx, svc)
 
+			// InterfaceTransaction may return empty on some services.
+			// Fall back to the static knownServiceNames map (reverse lookup).
+			if descriptor == "" || descriptor == "(unknown)" {
+				for desc, svcName := range knownServiceNames {
+					if svcName == name {
+						descriptor = desc
+						break
+					}
+				}
+			}
+
 			mode, err := cmd.Root().PersistentFlags().GetString("format")
 			if err != nil {
 				return fmt.Errorf("reading --format flag: %w", err)
 			}
 
 			if generatedRegistry == nil {
-				fmt.Fprintf(os.Stdout, "unknown interface %s — no methods in registry\n", descriptor)
-				return nil
+				return fmt.Errorf("no method registry available")
 			}
 
 			info := generatedRegistry.ByDescriptor(descriptor)
 			if info == nil {
-				fmt.Fprintf(os.Stdout, "unknown interface %s — no methods in registry\n", descriptor)
-				return nil
+				// Also try looking up by alias (the service name itself).
+				info = generatedRegistry.ByAlias(name)
+			}
+			if info == nil {
+				return fmt.Errorf("unknown interface %q for service %q — not in registry", descriptor, name)
 			}
 
 			f := NewFormatter(mode, os.Stdout)

tests/e2e/aidlcli_test.go

@@ -831,8 +831,6 @@ func TestAidlcli_Telephony_GetNetworkCountryIso(t *testing.T) {
 	stdout, stderr, err := runAidlcli(
 		"com.android.internal.telephony.ITelephony", "get-network-country-iso-for-phone",
 		"--phoneId=0",
-		"--callingPackage=com.android.shell",
-		"--callingFeatureId=none",
 	)
 	if err != nil {
 		combined := stderr + stdout