fix(android): 修复初次连接被误当成重连的bug

问题：
- waitForConnection() 在 channel 变成 READY 时无条件执行 reRegisterIfNeeded() 和 reSubscribeStreams()
- 导致初次连接时重复注册 party 和重复订阅事件流

修复：
- 使用 isReconnecting 标志区分初次连接和重连
- connect() 中确保 isReconnecting = false
- triggerReconnect() 设置 isReconnecting = true
- waitForConnection() 中先读取 isReconnecting 再重置，只有重连时才恢复流

添加详细日志用于调试：
- GrpcClient: connect(), doConnect(), waitForConnection(), triggerReconnect()
- TssRepository: registerParty(), restoreStreamsAfterReconnect(), onReconnectedCallback

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/remote/GrpcClient.kt

@@ -123,17 +123,26 @@ class GrpcClient @Inject constructor() {
      * Connect to the Message Router server
      */
     fun connect(host: String, port: Int) {
+        Log.d(TAG, "=== connect() called ===")
+        Log.d(TAG, "  host: $host, port: $port")
+        Log.d(TAG, "  isReconnecting before reset: ${isReconnecting.get()}")
+
         // Save connection params for reconnection
         currentHost = host
         currentPort = port
         shouldReconnect.set(true)
         reconnectAttempts.set(0)
 
+        // 重要：初次连接时确保 isReconnecting 为 false
+        // 这样 waitForConnection() 能正确区分初次连接和重连
+        isReconnecting.set(false)
+        Log.d(TAG, "  isReconnecting after reset: ${isReconnecting.get()} (should be false for first connect)")
+
         doConnect(host, port)
     }
 
     private fun doConnect(host: String, port: Int) {
-        Log.d(TAG, "Connecting to $host:$port")
+        Log.d(TAG, "doConnect: $host:$port, isReconnecting=${isReconnecting.get()}")
         _connectionState.value = GrpcConnectionState.Connecting
 
         try {
@@ -183,24 +192,39 @@ class GrpcClient @Inject constructor() {
 
                     when (state) {
                         ConnectivityState.READY -> {
-                            Log.d(TAG, "Connected successfully")
+                            // 关键修复：先读取 isReconnecting 再重置，用于区分初次连接和重连
+                            // - 初次连接：isReconnecting = false（由 connect() 触发）
+                            // - 重连：isReconnecting = true（由 triggerReconnect() 触发，包括后台唤醒）
+                            val wasReconnecting = isReconnecting.getAndSet(false)
+
+                            Log.d(TAG, "=== Channel READY ===")
+                            Log.d(TAG, "  wasReconnecting: $wasReconnecting")
+                            Log.d(TAG, "  registeredPartyId: $registeredPartyId")
+                            Log.d(TAG, "  eventStreamSubscribed: ${eventStreamSubscribed.get()}")
+                            Log.d(TAG, "  eventStreamPartyId: $eventStreamPartyId")
+
                             _connectionState.value = GrpcConnectionState.Connected
                             reconnectAttempts.set(0)
                             heartbeatFailCount.set(0)
-                            isReconnecting.set(false)
 
                             // Start channel state monitoring
                             startChannelStateMonitor()
 
-                            // Re-register if we were registered before
+                            // 只有重连时才需要恢复注册和订阅
-                            reRegisterIfNeeded()
+                            // 初次连接时，registerParty() 和 subscribeSessionEvents() 会在外部显式调用
+                            if (wasReconnecting) {
+                                Log.d(TAG, ">>> RECONNECT: Restoring registration and streams")
+                                // Re-register if we were registered before
+                                reRegisterIfNeeded()
+                                // Re-subscribe to streams
+                                reSubscribeStreams()
+                            } else {
+                                Log.d(TAG, ">>> FIRST CONNECT: Skipping restore (will be done by caller)")
+                            }
 
-                            // Restart heartbeat
+                            // Restart heartbeat (both first connect and reconnect need this)
                             startHeartbeat()
 
-                            // Re-subscribe to streams
-                            reSubscribeStreams()
-
                             return@withTimeout
                         }
                         ConnectivityState.TRANSIENT_FAILURE, ConnectivityState.SHUTDOWN -> {
@@ -347,7 +371,10 @@ class GrpcClient @Inject constructor() {
             Log.d(TAG, "Reconnecting in ${delay}ms (attempt $attempt/${reconnectConfig.maxRetries})")
             delay(delay)
 
-            isReconnecting.set(false)
+            // 注意：不要在这里重置 isReconnecting！
+            // isReconnecting 会在 waitForConnection() 的 READY 分支中被重置
+            // 这样 waitForConnection() 才能知道这是重连而非初次连接
+            Log.d(TAG, ">>> Starting reconnect, isReconnecting=$isReconnecting (should be true)")
             doConnect(host, port)
         }
     }

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

@@ -120,7 +120,7 @@ class TssRepository @Inject constructor(
     init {
         // Set up reconnection callback to restore streams
         grpcClient.setOnReconnectedCallback {
-            android.util.Log.d("TssRepository", "gRPC reconnected, restoring streams...")
+            android.util.Log.d("TssRepository", ">>> onReconnectedCallback triggered! <<<")
             restoreStreamsAfterReconnect()
         }
     }
@@ -129,22 +129,35 @@ class TssRepository @Inject constructor(
      * Restore message and event streams after gRPC reconnection
      */
     private fun restoreStreamsAfterReconnect() {
+        android.util.Log.d("TssRepository", "=== restoreStreamsAfterReconnect() called ===")
+
         val sessionId = currentMessageRoutingSessionId
         val partyIndex = currentMessageRoutingPartyIndex
         val routingPartyId = currentMessageRoutingPartyId
 
+        android.util.Log.d("TssRepository", "  currentMessageRoutingSessionId: $sessionId")
+        android.util.Log.d("TssRepository", "  currentMessageRoutingPartyIndex: $partyIndex")
+        android.util.Log.d("TssRepository", "  currentSessionEventPartyId: $currentSessionEventPartyId")
+        android.util.Log.d("TssRepository", "  grpcClient.wasEventStreamSubscribed(): ${grpcClient.wasEventStreamSubscribed()}")
+
         // Restore message routing if we had an active session
         if (sessionId != null && partyIndex != null) {
-            android.util.Log.d("TssRepository", "Restoring message routing for session: $sessionId, routingPartyId: $routingPartyId")
+            android.util.Log.d("TssRepository", "  >>> Restoring message routing for session: $sessionId")
             startMessageRouting(sessionId, partyIndex, routingPartyId)
+        } else {
+            android.util.Log.d("TssRepository", "  No active message routing to restore")
         }
 
         // Restore session event subscription with the correct partyId
         if (grpcClient.wasEventStreamSubscribed()) {
             val eventPartyId = currentSessionEventPartyId
-            android.util.Log.d("TssRepository", "Restoring session event subscription with partyId: $eventPartyId")
+            android.util.Log.d("TssRepository", "  >>> Restoring session event subscription with partyId: $eventPartyId")
             startSessionEventSubscription(eventPartyId)
+        } else {
+            android.util.Log.d("TssRepository", "  No event stream subscription to restore")
         }
+
+        android.util.Log.d("TssRepository", "=== restoreStreamsAfterReconnect() completed ===")
     }
 
     // HTTP client for API calls
@@ -231,22 +244,28 @@ class TssRepository @Inject constructor(
      * getOrCreatePartyId pattern). The partyId is loaded ONCE here and cached in memory.
      */
     suspend fun registerParty(): String {
+        android.util.Log.d("TssRepository", "=== registerParty() called ===")
+
         // Load or create persistent partyId (matching Electron's getOrCreatePartyId)
         val existingPartyId = appSettingDao.getValue("party_id")
         partyId = if (existingPartyId != null) {
-            android.util.Log.d("TssRepository", "Loaded existing partyId: $existingPartyId")
+            android.util.Log.d("TssRepository", "  Loaded existing partyId: $existingPartyId")
             existingPartyId
         } else {
             val newPartyId = UUID.randomUUID().toString()
             appSettingDao.setValue(AppSettingEntity("party_id", newPartyId))
-            android.util.Log.d("TssRepository", "Generated new partyId: $newPartyId")
+            android.util.Log.d("TssRepository", "  Generated new partyId: $newPartyId")
             newPartyId
         }
 
+        android.util.Log.d("TssRepository", "  Calling grpcClient.registerParty()...")
         grpcClient.registerParty(partyId, "temporary", "1.0.0")
+        android.util.Log.d("TssRepository", "  grpcClient.registerParty() completed")
 
         // Subscribe to session events immediately after registration (like Electron does)
+        android.util.Log.d("TssRepository", "  Calling startSessionEventSubscription()...")
         startSessionEventSubscription()
+        android.util.Log.d("TssRepository", "=== registerParty() completed ===")
 
         return partyId
     }