refactor: 统一 PG 连接串为一个 Default

- appsettings 的 ConnectionStrings 从 4 条 PG 连接串（Rag/File/Im/Workflow）
  合并为 1 条 Default（不含 Database）
- 各模块 Infrastructure 从 Default 派生连接串（拼接各自 Database 名）
  改一处连接信息，所有模块生效
- build 0/0

src/BuildFlow.Host/appsettings.json

@@ -18,18 +18,15 @@
   },
   "AllowedHosts": "*",
   "ConnectionStrings": {
-    "Rag": "Host=localhost;Port=5432;Database=rag;Username=rag;Password=REDACTED_DEV_PASSWORD",
-    "File": "Host=localhost;Port=5432;Database=file_system;Username=rag;Password=REDACTED_DEV_PASSWORD",
-    "Im": "Host=localhost;Port=5432;Database=im_system;Username=rag;Password=REDACTED_DEV_PASSWORD",
-    "Workflow": "Host=localhost;Port=5432;Database=workflow;Username=rag;Password=REDACTED_DEV_PASSWORD",
-    "MongoDb": "mongodb://mongo:mongo123@localhost:27017/im_system?authSource=admin",
-    "Redis": "localhost:6379,abortConnect=false"
+    "Default": "Host=43.134.235.58;Port=15432;Username=rag;Password=REDACTED_PG_PASSWORD",
+    "MongoDb": "mongodb://rag:CHANGE_ME@43.134.235.58:27017/im_system?authSource=admin",
+    "Redis": "43.134.235.58:16379,password=REDACTED_REDIS_PASSWORD,abortConnect=false"
   },
   "RabbitMq": {
-    "Host": "localhost",
-    "Port": 5672,
+    "Host": "43.134.235.58",
+    "Port": 25672,
     "Username": "rag",
-    "Password": "REDACTED_DEV_PASSWORD"
+    "Password": "REDACTED_RABBITMQ_PASSWORD"
   },
   "S3": {
     "Endpoint": "http://43.134.235.58:39200",

src/modules/file/Infrastructure/FileInfrastructureModule.cs

@@ -21,11 +21,11 @@ public class FileInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // DbContext 挂载审计拦截器，拦截器从 DI 容器解析 ICurrentUserContext
-        // 连接串优先读 "File" 键（聚合 host 用，与 rag 区分）；生产环境只有 "Default"，走 fallback 行为不变
-        var fsConnection = config.GetConnectionString("File") ?? config.GetConnectionString("Default");
+        // DbContext 挂载审计拦截器，统一从 Default 连接串派生（替换 Database 名）
+        var baseConn = config.GetConnectionString("Default")!;
+        var fsConn = $"{baseConn};Database=file_system";
         services.AddDbContext<FileDbContext>((sp, options) =>
-            options.UseNpgsql(fsConnection)
+            options.UseNpgsql(fsConn)
                    .AddInterceptors(sp.GetRequiredService<AuditInterceptor>()));
 
         // Scoped 生命周期：每个 HTTP 请求创建一个拦截器实例，确保 ICurrentUserContext 正确获取当前用户

src/modules/im/Infrastructure/IMInfrastructureModule.cs

@@ -23,11 +23,11 @@ public class IMInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // PostgreSQL：会话/参与者/群组/群成员。挂载 AuditInterceptor 自动写入审计字段与软删除
-        // 连接串优先读 "Im" 键（Admin Host 用，与 rag/file 区分）；设计时或模块测试只有 "Default" 时走 fallback
-        var imConnection = config.GetConnectionString("Im") ?? config.GetConnectionString("Default");
+        // PostgreSQL：会话/参与者/群组/群成员。统一从 Default 连接串派生（替换 Database 名）
+        var baseConn = config.GetConnectionString("Default")!;
+        var imConn = $"{baseConn};Database=im_system";
         services.AddDbContext<ImDbContext>((sp, options) =>
-            options.UseNpgsql(imConnection)
+            options.UseNpgsql(imConn)
                    .AddInterceptors(sp.GetRequiredService<AuditInterceptor>()));
         services.AddScoped<AuditInterceptor>();
 

src/modules/rag/Infrastructure/RAGInfrastructureModule.cs

@@ -27,10 +27,11 @@ public class RAGInfrastructureModule : AbpModule
         var config = services.GetConfiguration();
 
         // DbContext 挂载审计拦截器，拦截器从 DI 容器解析 ICurrentUserContext
-        // 连接串优先读 "Rag" 键（聚合 host 用，与 file-system 区分）；生产环境只有 "Default"，走 fallback 行为不变
-        var ragConnection = config.GetConnectionString("Rag") ?? config.GetConnectionString("Default");
+        // 统一从 Default 连接串派生（替换 Database 名），改一处连接信息全模块生效
+        var baseConn = config.GetConnectionString("Default")!;
+        var ragConn = $"{baseConn};Database=rag";
         services.AddDbContext<RagDbContext>((sp, options) =>
-            options.UseNpgsql(ragConnection, o => o.UseVector())
+            options.UseNpgsql(ragConn, o => o.UseVector())
                    .AddInterceptors(sp.GetRequiredService<AuditInterceptor>()));
 
         // Scoped 生命周期：每个 HTTP 请求创建一个拦截器实例，确保 ICurrentUserContext 正确获取当前用户

src/modules/workflow/Infrastructure/WorkflowInfrastructureModule.cs

@@ -19,11 +19,12 @@ public class WorkflowInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // 连接串优先读 "Workflow" 键（BuildFlow Host 用），否则回退 "Default"（设计时或模块测试）
-        var wfConnection = config.GetConnectionString("Workflow") ?? config.GetConnectionString("Default");
+        // 统一从 Default 连接串派生（替换 Database 名）
+        var baseConn = config.GetConnectionString("Default")!;
+        var wfConn = $"{baseConn};Database=workflow";
         services.AddDbContext<WorkflowDbContext>((sp, options) =>
         {
-            options.UseNpgsql(wfConnection, npgsql =>
+            options.UseNpgsql(wfConn, npgsql =>
             {
                 npgsql.MigrationsAssembly(typeof(WorkflowDbContext).Assembly.FullName);
             });