refactor(ios): share EventKit auth gating

apps/ios/Sources/EventKit/EventKitAuthorization.swift

@@ -0,0 +1,34 @@
+import EventKit
+
+enum EventKitAuthorization {
+    static func allowsRead(status: EKAuthorizationStatus) -> Bool {
+        switch status {
+        case .authorized, .fullAccess:
+            return true
+        case .writeOnly:
+            return false
+        case .notDetermined:
+            // Don’t prompt during node.invoke; prompts block the invoke and lead to timeouts.
+            return false
+        case .restricted, .denied:
+            return false
+        @unknown default:
+            return false
+        }
+    }
+
+    static func allowsWrite(status: EKAuthorizationStatus) -> Bool {
+        switch status {
+        case .authorized, .fullAccess, .writeOnly:
+            return true
+        case .notDetermined:
+            // Don’t prompt during node.invoke; prompts block the invoke and lead to timeouts.
+            return false
+        case .restricted, .denied:
+            return false
+        @unknown default:
+            return false
+        }
+    }
+}
+