Wire Warning Dialog audit log on coordinator decision

Inject DuplicateWarningEventLogger into the dialog via constructor parameter (not service locator) to keep the widget testable. Make the Proceed button's onPressed an async handler: set a local isLoading state variable (using StatefulWidget or a simple ValueNotifier) to show a loading indicator, then await the log call, then pop with the result. Use a try/catch around the log call to catch Supabase or network errors and surface them as an inline error string below the buttons — do not use a SnackBar as it may not be accessible from within the modal focus trap. Source coordinatorId from a repository/auth service injected at the call site — the parent widget should pass it in as part of DuplicateActivityWarning or as a separate constructor argument.

Keep the logger interface thin: logWarningAcknowledged and logWarningDismissed should both return Future and throw on failure so the dialog can handle errors consistently.

Write unit tests using flutter_test and mockito (or mocktail): (1) mock DuplicateWarningEventLogger and verify logWarningAcknowledged is called with correct warningId, coordinatorId, and a recent UTC timestamp when Proceed is tapped, (2) verify logWarningDismissed is called when Cancel is tapped, (3) verify DialogResult.proceed is returned on successful acknowledge, (4) verify DialogResult.cancelled is returned on cancel, (5) simulate logWarningAcknowledged throwing an exception and assert the dialog remains open with an error message displayed. Test the loading state by using a completer to delay the mock and assert the Proceed button shows a loading indicator during the async call.