fix(android): ensure session event subscription active before creating sign session

Add ensureSessionEventSubscriptionActive() call at the start of createSignSession()
to prevent race condition where session_started event arrives before subscription
is ready. Also add debug logging for _signSessionId and pendingSignInitiatorInfo
in event callback to help diagnose sign initiator event matching issues.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/mpc-system/services/service-party-android/app/src/main/java/com/durian/tssparty/data/repository/TssRepository.kt

@@ -1936,6 +1936,11 @@ class TssRepository @Inject constructor(
     ): Result<SignSessionResult> {
         return withContext(Dispatchers.IO) {
             try {
+                // CRITICAL: Ensure session event subscription is active BEFORE creating sign session
+                // This prevents race condition where session_started event arrives before subscription is ready
+                android.util.Log.d("TssRepository", "[CO-SIGN] Ensuring session event subscription is active before creating sign session")
+                ensureSessionEventSubscriptionActive()
+
                 // Get share record
                 val shareEntity = shareRecordDao.getShareById(shareId)
                     ?: return@withContext Result.failure(Exception("Share not found"))
@@ -2145,8 +2150,15 @@ class TssRepository @Inject constructor(
                     ?: return@withContext Result.failure(Exception("Share not found"))
 
                 android.util.Log.d("TssRepository", "[CO-SIGN] startSigning: participants=${session.participants.size}")
+                android.util.Log.d("TssRepository", "[CO-SIGN] startSigning: sessionId=$sessionId, partyId=$partyId, partyIndex=${shareEntity.partyIndex}")
+                android.util.Log.d("TssRepository", "[CO-SIGN] startSigning: thresholdT=${session.thresholdT}, thresholdN=${shareEntity.thresholdN}")
+                android.util.Log.d("TssRepository", "[CO-SIGN] startSigning: messageHash=${session.messageHash?.take(20)}...")
+                session.participants.forEachIndexed { idx, p ->
+                    android.util.Log.d("TssRepository", "[CO-SIGN] startSigning: participant[$idx] = ${p.partyId.take(12)}..., index=${p.partyIndex}")
+                }
 
                 // Start TSS sign
+                android.util.Log.d("TssRepository", "[CO-SIGN] Calling tssNativeBridge.startSign...")
                 val startResult = tssNativeBridge.startSign(
                     sessionId = sessionId,
                     partyId = partyId,
@@ -2158,10 +2170,13 @@ class TssRepository @Inject constructor(
                     shareData = shareEntity.encryptedShare,
                     password = password
                 )
+                android.util.Log.d("TssRepository", "[CO-SIGN] tssNativeBridge.startSign returned: isSuccess=${startResult.isSuccess}")
 
                 if (startResult.isFailure) {
+                    android.util.Log.e("TssRepository", "[CO-SIGN] startSign FAILED: ${startResult.exceptionOrNull()?.message}")
                     return@withContext Result.failure(startResult.exceptionOrNull()!!)
                 }
+                android.util.Log.d("TssRepository", "[CO-SIGN] startSign succeeded, starting progress collection...")
 
                 // Start collecting progress from native bridge
                 startProgressCollection()

backend/mpc-system/services/service-party-android/app/src/main/java/com/durian/tssparty/presentation/viewmodel/MainViewModel.kt

@@ -329,6 +329,8 @@ class MainViewModel @Inject constructor(
             android.util.Log.d("MainViewModel", "  _currentSessionId: ${_currentSessionId.value}")
             android.util.Log.d("MainViewModel", "  pendingJoinKeygenInfo?.sessionId: ${pendingJoinKeygenInfo?.sessionId}")
             android.util.Log.d("MainViewModel", "  pendingJoinSignInfo?.sessionId: ${pendingJoinSignInfo?.sessionId}")
+            android.util.Log.d("MainViewModel", "  _signSessionId: ${_signSessionId.value}")
+            android.util.Log.d("MainViewModel", "  pendingSignInitiatorInfo?.sessionId: ${pendingSignInitiatorInfo?.sessionId}")
 
             when (event.eventType) {
                 "session_started" -> {
@@ -362,9 +364,12 @@ class MainViewModel @Inject constructor(
 
                     // Check if this is for sign initiator (TransferScreen - 发起签名)
                     val signSessionId = _signSessionId.value
+                    android.util.Log.d("MainViewModel", "Checking for sign initiator: signSessionId=$signSessionId, eventSessionId=${event.sessionId}")
                     if (signSessionId != null && event.sessionId == signSessionId) {
                         android.util.Log.d("MainViewModel", "Session started event for sign initiator, triggering sign")
                         startSignAsInitiator(event.selectedParties)
+                    } else {
+                        android.util.Log.d("MainViewModel", "NOT triggering sign initiator: signSessionId=$signSessionId, pendingSignInitiatorInfo=${pendingSignInitiatorInfo?.sessionId}")
                     }
                 }
                 "party_joined", "participant_joined" -> {
@@ -1218,22 +1223,30 @@ class MainViewModel @Inject constructor(
      * Start the TSS signing process
      */
     private fun startSigningProcess(sessionId: String, shareId: Long, password: String) {
+        android.util.Log.d("MainViewModel", "[SIGN] startSigningProcess called: sessionId=$sessionId, shareId=$shareId")
         viewModelScope.launch {
+            android.util.Log.d("MainViewModel", "[SIGN] Calling repository.startSigning...")
             val startResult = repository.startSigning(sessionId, shareId, password)
+            android.util.Log.d("MainViewModel", "[SIGN] repository.startSigning returned: isSuccess=${startResult.isSuccess}")
 
             if (startResult.isFailure) {
+                android.util.Log.e("MainViewModel", "[SIGN] startSigning FAILED: ${startResult.exceptionOrNull()?.message}")
                 _uiState.update { it.copy(error = startResult.exceptionOrNull()?.message) }
                 return@launch
             }
 
             // Wait for signature
+            android.util.Log.d("MainViewModel", "[SIGN] startSigning succeeded, calling waitForSignature...")
             val signResult = repository.waitForSignature()
+            android.util.Log.d("MainViewModel", "[SIGN] waitForSignature returned: isSuccess=${signResult.isSuccess}")
 
             signResult.fold(
                 onSuccess = { result ->
+                    android.util.Log.d("MainViewModel", "[SIGN] Signature received: ${result.signature.take(20)}...")
                     _signature.value = result.signature
                 },
                 onFailure = { e ->
+                    android.util.Log.e("MainViewModel", "[SIGN] waitForSignature FAILED: ${e.message}")
                     _uiState.update { it.copy(error = e.message) }
                 }
             )