fix: audit remediation — SSE user scoping, FK transactional safety, UI error handling

- H4: scoped SSE import progress to exact userId match; non-HTTP events excluded from all subscribers
- H2: moved PRAGMA foreign_key_check inside SQLite transaction before COMMIT; violations rollback preserving old tables
- M1: removed dead axios-style error branch from extractErrorMessage (interceptor already unwraps)
- M2: split handleSave try/catch — save errors vs reload errors shown distinctly
- M3: added provider field validation before AI config test request
- Added SSE scoping regression tests (import service + controller)
- Added FK check failure rollback test (database-migrations.spec)
- Updated controller spec expectations for userId parameter

Co-authored-by: Code Review <branch-review>

apps/server/src/classes/classes.module.ts

@@ -1,13 +1,13 @@
 import { Module } from '@nestjs/common';
 import { TypeOrmModule } from '@nestjs/typeorm';
-import { Class, ClassStudent, ClassTeacher, ClassSchedule, AttendanceRecord, Student, StudentDingMapping } from '../entities';
+import { Class, ClassStudent, ClassTeacher, ClassSchedule, AttendanceRecord, AttendanceSession, Student, StudentDingMapping } from '../entities';
 import { ClassesService } from './classes.service';
 import { ClassesController } from './classes.controller';
 import { OperationLogsModule } from '../operation-logs/operation-logs.module';
 import { NotificationsModule } from '../notifications/notifications.module';
 
 @Module({
-  imports: [TypeOrmModule.forFeature([Class, ClassStudent, ClassTeacher, ClassSchedule, AttendanceRecord, Student, StudentDingMapping]), OperationLogsModule, NotificationsModule],
+  imports: [TypeOrmModule.forFeature([Class, ClassStudent, ClassTeacher, ClassSchedule, AttendanceRecord, AttendanceSession, Student, StudentDingMapping]), OperationLogsModule, NotificationsModule],
   controllers: [ClassesController],
   providers: [ClassesService],
   exports: [ClassesService],