refactor: 连接串全部回归 Host appsettings 管理，模块零拼接

- Host appsettings 配各模块完整连接串（Default/File/Im/Workflow）
- 模块 Infrastructure 只 GetConnectionString 读自己的 key，不做任何拼接
- 删除 baseConn/Database=xxx 拼接逻辑
- build 0/0

src/BuildFlow.Host/appsettings.json

@@ -18,7 +18,10 @@
   },
   "AllowedHosts": "*",
   "ConnectionStrings": {
-    "Default": "Host=43.134.235.58;Port=15432;Username=rag;Password=REDACTED_PG_PASSWORD",
+    "Default": "Host=43.134.235.58;Port=15432;Database=rag;Username=rag;Password=REDACTED_PG_PASSWORD",
+    "File": "Host=43.134.235.58;Port=15432;Database=file_system;Username=rag;Password=REDACTED_PG_PASSWORD",
+    "Im": "Host=43.134.235.58;Port=15432;Database=im_system;Username=rag;Password=REDACTED_PG_PASSWORD",
+    "Workflow": "Host=43.134.235.58;Port=15432;Database=workflow;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"
   },

src/modules/file/Infrastructure/FileInfrastructureModule.cs

@@ -21,11 +21,9 @@ public class FileInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // DbContext 挂载审计拦截器，统一从 Default 连接串派生（替换 Database 名）
+        // DbContext 挂载审计拦截器；连接串由 Host appsettings 的 ConnectionStrings:File 提供
-        var baseConn = config.GetConnectionString("Default")!;
-        var fsConn = $"{baseConn};Database=file_system";
         services.AddDbContext<FileDbContext>((sp, options) =>
-            options.UseNpgsql(fsConn)
+            options.UseNpgsql(config.GetConnectionString("File")!)
                    .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 +23,9 @@ public class IMInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // PostgreSQL：会话/参与者/群组/群成员。统一从 Default 连接串派生（替换 Database 名）
+        // PostgreSQL：会话/参与者/群组/群成员。连接串由 Host appsettings 的 ConnectionStrings:Im 提供
-        var baseConn = config.GetConnectionString("Default")!;
-        var imConn = $"{baseConn};Database=im_system";
         services.AddDbContext<ImDbContext>((sp, options) =>
-            options.UseNpgsql(imConn)
+            options.UseNpgsql(config.GetConnectionString("Im")!)
                    .AddInterceptors(sp.GetRequiredService<AuditInterceptor>()));
         services.AddScoped<AuditInterceptor>();
 

src/modules/rag/Infrastructure/RAGInfrastructureModule.cs

@@ -26,12 +26,9 @@ public class RAGInfrastructureModule : 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
+        // DbContext 挂载审计拦截器；连接串由 Host appsettings 的 ConnectionStrings:Default 提供
-        // 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(ragConn, o => o.UseVector())
+            options.UseNpgsql(config.GetConnectionString("Default")!, 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

@@ -19,12 +19,10 @@ public class WorkflowInfrastructureModule : AbpModule
         var services = context.Services;
         var config = services.GetConfiguration();
 
-        // 统一从 Default 连接串派生（替换 Database 名）
+        // 连接串由 Host appsettings 的 ConnectionStrings:Workflow 提供
-        var baseConn = config.GetConnectionString("Default")!;
-        var wfConn = $"{baseConn};Database=workflow";
         services.AddDbContext<WorkflowDbContext>((sp, options) =>
         {
-            options.UseNpgsql(wfConn, npgsql =>
+            options.UseNpgsql(config.GetConnectionString("Workflow")!, npgsql =>
             {
                 npgsql.MigrationsAssembly(typeof(WorkflowDbContext).Assembly.FullName);
             });