fix(service-party-android): 修复导入钱包签名时 'party not registered' 错误

导入的钱包份额携带原始 keygen partyId，与设备自身 partyId 不同。
签名时用原始 partyId 订阅 session events，但该 ID 未在 message-router
注册，导致服务端返回 FAILED_PRECONDITION。

修复：签名前将导入份额的 partyId 也注册到 message-router（带 3 次重试），
注册失败则中断签名流程并提示用户；断线重连时自动恢复双 partyId 注册；
签名结束后清理额外注册。

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

@@ -97,6 +97,11 @@ class GrpcClient @Inject constructor() {
     private var registeredPartyId: String? = null
     private var registeredPartyRole: String? = null
 
+    // Additional signing party registration (for imported/restored shares)
+    // When signing with a restored wallet, the signing partyId differs from the device partyId
+    // and must also be registered with the message-router
+    private var registeredSigningPartyId: String? = null
+
     // Heartbeat state
     private var heartbeatJob: Job? = null
     private val heartbeatFailCount = AtomicInteger(0)
@@ -460,6 +465,17 @@ class GrpcClient @Inject constructor() {
                 Log.e(TAG, "Re-registration failed: ${e.message}")
             }
         }
+
+        // Also re-register the signing partyId if active (for imported/restored shares)
+        val signingId = registeredSigningPartyId
+        if (signingId != null && signingId != partyId) {
+            Log.d(TAG, "Re-registering signing party: $signingId")
+            try {
+                registerPartyInternal(signingId, "temporary", "1.0.0")
+            } catch (e: Exception) {
+                Log.e(TAG, "Re-registration of signing party failed: ${e.message}")
+            }
+        }
     }
 
     /**
@@ -651,6 +667,29 @@ class GrpcClient @Inject constructor() {
         }
     }
 
+    /**
+     * Register an additional signing partyId with the message-router.
+     * Used when signing with imported/restored shares where the signing partyId
+     * differs from the device's own partyId. Does not overwrite the device registration.
+     */
+    suspend fun registerSigningParty(signingPartyId: String): Result<Boolean> = withContext(Dispatchers.IO) {
+        if (signingPartyId == registeredPartyId) {
+            // Same as device partyId, already registered
+            return@withContext Result.success(true)
+        }
+        Log.d(TAG, "Registering signing partyId: $signingPartyId (device partyId: $registeredPartyId)")
+        registeredSigningPartyId = signingPartyId
+        registerPartyInternal(signingPartyId, "temporary", "1.0.0")
+    }
+
+    /**
+     * Clear the additional signing party registration.
+     * Called when signing completes or fails.
+     */
+    fun clearSigningPartyRegistration() {
+        registeredSigningPartyId = null
+    }
+
     /**
      * Join a session
      */

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

@@ -388,12 +388,34 @@ class TssRepository @Inject constructor(
      *        CRITICAL: For signing with restored wallets, this should be the original
      *        partyId from keygen (shareEntity.partyId).
      */
-    private fun ensureSessionEventSubscriptionActive(signingPartyId: String? = null) {
+    private suspend fun ensureSessionEventSubscriptionActive(signingPartyId: String? = null) {
         // Check if the session event job is still active
         val isActive = sessionEventJob?.isActive == true
         val effectivePartyId = signingPartyId ?: currentSessionEventPartyId ?: partyId
         android.util.Log.d("TssRepository", "Checking session event subscription: isActive=$isActive, effectivePartyId=$effectivePartyId")
 
+        // If subscribing with a different partyId (imported/restored share),
+        // register it with the message-router first to avoid "party not registered" error.
+        // Retry up to 3 times to handle transient network issues.
+        if (effectivePartyId != partyId) {
+            var registered = false
+            for (attempt in 1..3) {
+                android.util.Log.d("TssRepository", "Registering signing partyId before subscribing: $effectivePartyId (attempt $attempt/3)")
+                val regResult = grpcClient.registerSigningParty(effectivePartyId)
+                if (regResult.isSuccess) {
+                    registered = true
+                    break
+                }
+                android.util.Log.e("TssRepository", "Failed to register signing partyId (attempt $attempt/3): ${regResult.exceptionOrNull()?.message}")
+                if (attempt < 3) {
+                    kotlinx.coroutines.delay(1000L * attempt)
+                }
+            }
+            if (!registered) {
+                throw Exception("无法注册签名方 $effectivePartyId，请检查网络连接后重试")
+            }
+        }
+
         if (!isActive) {
             android.util.Log.w("TssRepository", "Session event subscription is not active, restarting...")
             startSessionEventSubscription(signingPartyId)
@@ -1427,6 +1449,7 @@ class TssRepository @Inject constructor(
             pendingSessionId = null  // Clear pending session ID on completion
             messageCollectionJob?.cancel()
             currentSigningPartyId = null  // Clear after signing completes
+            grpcClient.clearSigningPartyRegistration()
 
             android.util.Log.d("TssRepository", "Sign as joiner completed: signature=${result.signature.take(20)}...")
 
@@ -1438,6 +1461,7 @@ class TssRepository @Inject constructor(
             _sessionStatus.value = SessionStatus.FAILED
             pendingSessionId = null  // Clear pending session ID on failure
             currentSigningPartyId = null  // Clear on failure too
+            grpcClient.clearSigningPartyRegistration()
             Result.failure(e)
         }
     }
@@ -1734,6 +1758,7 @@ class TssRepository @Inject constructor(
             _sessionStatus.value = SessionStatus.COMPLETED
             messageCollectionJob?.cancel()
             currentSigningPartyId = null  // Clear after signing completes
+            grpcClient.clearSigningPartyRegistration()
 
             Result.success(result)
 
@@ -1741,6 +1766,7 @@ class TssRepository @Inject constructor(
             android.util.Log.e("TssRepository", "Join sign session failed", e)
             _sessionStatus.value = SessionStatus.FAILED
             currentSigningPartyId = null  // Clear on failure too
+            grpcClient.clearSigningPartyRegistration()
             Result.failure(e)
         }
     }
@@ -2764,10 +2790,12 @@ class TssRepository @Inject constructor(
                 _sessionStatus.value = SessionStatus.COMPLETED
                 messageCollectionJob?.cancel()
                 currentSigningPartyId = null  // Clear after signing completes
+                grpcClient.clearSigningPartyRegistration()
 
                 Result.success(result)
             } catch (e: Exception) {
                 _sessionStatus.value = SessionStatus.FAILED
+                grpcClient.clearSigningPartyRegistration()
                 Result.failure(e)
             }
         }