notifications: add NSLog diagnostics + explicit .active interruption level

Helps diagnose why .list-style entries aren't landing in Notification
Center on macOS — logs willPresent firing and the add() result so we can
distinguish 'delivery never happened' from 'system filtered the entry'.

macos/Classes/NotificationsPlugin.swift

@@ -137,11 +137,19 @@ public class NotificationsPlugin: NSObject, NativePlugin, FlutterStreamHandler,
         if let t = threadId { content.threadIdentifier = t }
         content.userInfo = data
         content.sound = .default
+        // .active is the implicit default but spelling it out clarifies that
+        // we want both a banner AND a Notification Center entry. .passive
+        // would suppress the banner; .timeSensitive would pierce focus.
+        if #available(macOS 12.0, *) {
+            content.interruptionLevel = .active
+        }
 
         let request = UNNotificationRequest(identifier: id, content: content, trigger: nil)
         UNUserNotificationCenter.current().add(request) { error in
             if let error = error {
                 NSLog("ux notifications: add failed: \(error)")
+            } else {
+                NSLog("ux notifications: posted id=\(id) thread=\(threadId ?? "-")")
             }
         }
     }
@@ -203,9 +211,12 @@ public class NotificationsPlugin: NSObject, NativePlugin, FlutterStreamHandler,
         // it as a banner — entries never reach Notification Center. The
         // 11+ split is `.banner` + `.list`; we need both so the toast
         // shows AND persists in the tray.
+        let id = notification.request.identifier
         if #available(macOS 11.0, *) {
+            NSLog("ux notifications: willPresent id=\(id) → [.banner, .list, .sound]")
             completionHandler([.banner, .list, .sound])
         } else {
+            NSLog("ux notifications: willPresent id=\(id) → [.alert, .sound]")
             completionHandler([.alert, .sound])
         }
     }