Add own device creation ts in crypto API

MatrixSDK/Crypto/MXCrypto.h

@@ -95,6 +95,12 @@ extern NSString *const MXDeviceListDidUpdateUsersDevicesNotification;
  */
 @property (nullable, nonatomic, readonly) NSString *deviceEd25519Key;
 
+
+/**
+* The user device creation in local timestamp, milliseconds since epoch.
+*/
+@property (nonatomic) UInt64 deviceCreationTs;
+
 /**
  The key backup manager.
  */

MatrixSDK/Crypto/MXCrypto.m

@@ -1422,6 +1422,12 @@ - (NSString *)olmVersion
 #endif
 }
 
+- (uint64_t)deviceCreationTs
+{
+    // Device creation timestamp is not support in legacy crypto
+    return 0;
+}
+
 
 #pragma mark - Gossipping
 

MatrixSDK/Crypto/MXCryptoV2.swift

@@ -19,7 +19,7 @@
 
 /// An implementation of `MXCrypto` which uses [matrix-rust-sdk](https://github.com/matrix-org/matrix-rust-sdk/tree/main/crates/matrix-sdk-crypto)
 /// under the hood.
 class MXCryptoV2: NSObject, MXCrypto {
     enum Error: Swift.Error {
         case cannotUnsetTrust
         case backupNotEnabled
@@ -56,6 +56,11 @@
         return machine.deviceEd25519Key
     }
 
+    var deviceCreationTs: UInt64 {
+        // own device always exists
+        return machine.device(userId: machine.userId, deviceId: machine.deviceId)!.firstTimeSeenTs
+    }
+
     let backup: MXKeyBackup?
     let keyVerificationManager: MXKeyVerificationManager
     let crossSigning: MXCrossSigning