feat(service-party-app): 添加获取已注册参与方列表API

新增 grpc.getRegisteredParties() API，用于查询 Message Router 中已注册的参与方：
- grpc-client.ts: 添加 getRegisteredParties() 方法
- main.ts: 添加 IPC 处理器
- preload.ts: 暴露 API 到渲染进程
- electron.d.ts: 添加类型定义

此功能用于测试和调试，确认 Service-Party-App 是否成功注册到 Message Router。

🤖 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-app/electron/main.ts

@@ -217,6 +217,16 @@ function setupIpcHandlers() {
     }
   });
 
+  // gRPC - 获取已注册的参与方列表
+  ipcMain.handle('grpc:getRegisteredParties', async (_event, { roleFilter, onlyOnline }) => {
+    try {
+      const parties = await grpcClient?.getRegisteredParties(roleFilter, onlyOnline);
+      return { success: true, parties: parties || [] };
+    } catch (error) {
+      return { success: false, error: (error as Error).message, parties: [] };
+    }
+  });
+
   // gRPC - 验证签名会话 (通过 Account 服务 HTTP API)
   ipcMain.handle('grpc:validateSigningSession', async (_event, { code }) => {
     try {

backend/mpc-system/services/service-party-app/electron/modules/grpc-client.ts

@@ -78,6 +78,18 @@ interface SessionEvent {
   messageHash?: Buffer;
 }
 
+interface RegisteredParty {
+  partyId: string;
+  role: string;
+  online: boolean;
+  registeredAt: string;
+  lastSeenAt: string;
+}
+
+interface GetRegisteredPartiesResponse {
+  parties: RegisteredParty[];
+}
+
 /**
  * gRPC 客户端 - 连接到 Message Router
  *
@@ -390,4 +402,40 @@ export class GrpcClient extends EventEmitter {
         );
     });
   }
+
+  /**
+   * 获取已注册的参与方列表
+   * @param roleFilter 可选，按角色过滤 (persistent/delegate/temporary)
+   * @param onlyOnline 可选，只返回在线的参与方
+   */
+  async getRegisteredParties(roleFilter?: string, onlyOnline?: boolean): Promise<RegisteredParty[]> {
+    if (!this.client) {
+      throw new Error('Not connected');
+    }
+
+    return new Promise((resolve, reject) => {
+      (this.client as grpc.Client & { getRegisteredParties: (req: unknown, callback: (err: Error | null, res: GetRegisteredPartiesResponse) => void) => void })
+        .getRegisteredParties(
+          {
+            role_filter: roleFilter || '',
+            only_online: onlyOnline || false,
+          },
+          (err: Error | null, response: GetRegisteredPartiesResponse) => {
+            if (err) {
+              reject(err);
+            } else {
+              // 转换字段名从 snake_case 到 camelCase
+              const parties = (response.parties || []).map((p: { party_id?: string; partyId?: string; role?: string; party_role?: string; online?: boolean; registered_at?: string; registeredAt?: string; last_seen_at?: string; lastSeenAt?: string }) => ({
+                partyId: p.party_id || p.partyId || '',
+                role: p.role || p.party_role || '',
+                online: p.online || false,
+                registeredAt: p.registered_at || p.registeredAt || '',
+                lastSeenAt: p.last_seen_at || p.lastSeenAt || '',
+              }));
+              resolve(parties);
+            }
+          }
+        );
+    });
+  }
 }

backend/mpc-system/services/service-party-app/electron/preload.ts

@@ -42,6 +42,10 @@ contextBridge.exposeInMainWorld('electronAPI', {
     testConnection: (url: string) =>
       ipcRenderer.invoke('grpc:testConnection', { url }),
 
+    // 获取已注册的参与方列表
+    getRegisteredParties: (roleFilter?: string, onlyOnline?: boolean) =>
+      ipcRenderer.invoke('grpc:getRegisteredParties', { roleFilter, onlyOnline }),
+
     // 签名相关
     validateSigningSession: (code: string) =>
       ipcRenderer.invoke('grpc:validateSigningSession', { code }),

backend/mpc-system/services/service-party-app/src/types/electron.d.ts

@@ -146,6 +146,21 @@ interface TestConnectionResult {
   error?: string;
 }
 
+// 已注册的参与方
+interface RegisteredParty {
+  partyId: string;
+  role: string;
+  online: boolean;
+  registeredAt: string;
+  lastSeenAt: string;
+}
+
+interface GetRegisteredPartiesResult {
+  success: boolean;
+  parties: RegisteredParty[];
+  error?: string;
+}
+
 interface SessionEvent {
   type: 'participant_joined' | 'status_changed' | 'completed' | 'failed';
   participant?: Participant;
@@ -413,6 +428,8 @@ interface ElectronAPI {
     getSessionStatus: (sessionId: string) => Promise<GetSessionStatusResult>;
     subscribeSessionEvents: (sessionId: string, callback: (event: SessionEvent) => void) => () => void;
     testConnection: (url: string) => Promise<TestConnectionResult>;
+    // 获取已注册的参与方列表
+    getRegisteredParties: (roleFilter?: string, onlyOnline?: boolean) => Promise<GetRegisteredPartiesResult>;
     // 签名相关
     validateSigningSession: (code: string) => Promise<ValidateSigningSessionResult>;
     joinSigningSession: (params: JoinSigningSessionParams) => Promise<JoinSigningSessionResult>;