fix: prevent duplicate onSPUIReady delivery from repeated rendering app events

[sampaioroberto]

Problem

Crash reported via Firebase Crashlytics:

Application tried to present modally a view controller <ConsentViewController.GenericWebMessageViewController: 0x1318ffe00> that is already being presented by <HostApp.SomeViewController: 0x131913200>.

The same GenericWebMessageViewController instance was triggering delegate.onSPUIReady() more than once. Host apps following the documented pattern (present(controller, animated: true) inside onSPUIReady) would crash on the second call.

Root cause

SPJSReceiver.js converts a sp.showMessage (without fromPM) postMessage into an onMessageReady native event. If the rendering app fires this event more than once for the same view, the Swift side had no idempotency guard:

// before — no guard
func onMessageReady() {
    timeoutWorkItem.cancel()
    webview?.evaluateJavaScript(...)
    messageUIDelegate?.loaded(self)  // called N times if event fires N times
}

onPmReady() had a partial guard via isFirstLayerMessage, but that flag guards a state-machine transition (first layer → PM), not duplicate events on the same path.

Fix

Add a hasCalledLoaded boolean flag to GenericWebMessageViewController that ensures loaded() — and therefore onSPUIReady() — is delivered at most once per controller instance, regardless of how many JS events arrive.

private var hasCalledLoaded = false

func onMessageReady() {
    timeoutWorkItem.cancel()
    guard !hasCalledLoaded else { return }
    hasCalledLoaded = true
    webview?.evaluateJavaScript(...)
    messageUIDelegate?.loaded(self)
}

func onPmReady() {
    timeoutWorkItem.cancel()
    guard isFirstLayerMessage, !hasCalledLoaded else { return }
    hasCalledLoaded = true
    messageUIDelegate?.loaded(self)
}

The two guards are orthogonal: isFirstLayerMessage remains for its original purpose (suppress PM-ready when coming from a first-layer flow); hasCalledLoaded adds the missing idempotency invariant across both paths.

Test

Added DuplicatingRenderingAppMock — a WKWebView subclass that fires sp.showMessage twice in the same tick — and a regression test that asserts loadedCallCount == 1.

• Before fix: loadedCallCount would be 2 → test fails
• After fix: loadedCallCount is 1 → test passes ✅

All 5 tests in GenericWebMessageViewControllerSpec pass.

🤖 Generated with Claude Code

[andresilveirah]

Hi @sampaioroberto thank you for the PR. I've made a small modification, instead of relying on a boolean flag, I check if the ViewController is currently being presented or its view is != nil. I've used your tests and created #650 . I'm closing this PR in favour of that one.