Add dedicated wait/success/error screens for transaction status

After broadcast, the user is taken to a full-screen wait view showing
the amount, recipient, tx hash (copyable + etherscan link), and a
count-up timer. The view polls every 10 seconds for confirmation.

On confirmation: navigates to success screen showing block number,
tx hash, and a Done button that returns to the address view.

On 60-second timeout or error: navigates to error screen with the
failure message, tx hash (if available), and Done button.

Replaces the previous inline confirm-status div that was crammed
onto the confirmation page.

src/popup/views/helpers.js

@@ -16,6 +16,9 @@ const VIEWS = [
     "address-token",
     "send",
     "confirm-tx",
+    "wait-tx",
+    "success-tx",
+    "error-tx",
     "receive",
     "add-token",
     "settings",