feat(wallet): add no-wallet guard for /pay and fix payment event type

Phase 3b: Deferred features completion

Task 1: /pay No-Wallet Guard
- Add noWalletSetup and isCheckingWallet flags to PaymentEntryState
- Update PaymentEntryPresenter to check wallet state early via collectAsState
- Add full-screen "Wallet Required" prompt to PaymentEntryView when no wallet
- Add onOpenWalletSettings callback through the entire navigation chain
- Wire callback in MessagesFlowNode to navigate to WalletPanel

Task 2: Payment Timeline Card (already existed, just fixed event type)
- Fix isPaymentEventType() to check for correct event types:
  - co.sulkta.payment.request (was incorrectly com.sulkta.cardano.payment)
  - co.sulkta.payment.status (for status updates)

Build verified: assembleGplayDebug passes

features/messages/impl/src/main/kotlin/io/element/android/features/messages/impl/MessagesFlowNode.kt

@@ -567,6 +567,11 @@ class MessagesFlowNode(
                     override fun onPaymentCancelled() {
                         backstack.pop()
                     }
+
+                    override fun onOpenWalletSettings() {
+                        backstack.pop()
+                        backstack.push(NavTarget.WalletPanel)
+                    }
                 }
                 walletEntryPoint.paymentFlowBuilder(
                     parentNode = this,