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/wallet/api/src/main/kotlin/io/element/android/features/wallet/api/WalletEntryPoint.kt

@@ -44,5 +44,7 @@ interface WalletEntryPoint : FeatureEntryPoint {
     interface Callback : Plugin {
         fun onPaymentSent(txHash: String)
         fun onPaymentCancelled()
+        /** Called when user needs to set up wallet before paying. Caller should navigate to wallet panel. */
+        fun onOpenWalletSettings()
     }
 }