[app-attest-env] Log the actual error behind guest-session App Attest failures

Guest session handshake fails silently after the challenge step - no
console output, just a generic "could not load" message in the UI.
DCAppAttestService errors (generateKey/attestKey/generateAssertion)
propagate up uncaught by anything that logs them. Add explicit logging
at each step so the real thrown error is visible instead of debugging
blind.

Sources/PediFoods/Views/Main/PublicLocationPickerView.swift

@@ -161,6 +161,7 @@ struct PublicLocationPickerView: View {
                 errorMessage = "Nenhum estado disponível no momento."
             }
         } catch {
+            print("[PublicLocationPickerView] loadLocations failed: \(error)")
             errorMessage = "Não foi possível carregar. Tente novamente."
         }
         isLoading = false