feat: add wagon usage computation and maintenance logging features

- Implemented  utility to calculate wagon usage metrics for train schedules.
- Created  for sending wagons to maintenance with optional notes.
- Added unit tests for train builder maintenance functionalities, including formatting train run labels and building maintenance notes.
- Developed  component for merging train schedules with detailed previews and reasons for merging.
- Introduced  component for selecting wagons with search functionality and selection limits.
- Created  for displaying and filtering audit logs, including detailed views of individual log entries.
- Added  for handling API interactions related to audit logs, including fetching logs and entity types.

apps/edr-freight-api/src/modules/audit/audit.module.ts

@@ -0,0 +1,34 @@
+import { Global, Module } from '@nestjs/common';
+import { APP_INTERCEPTOR } from '@nestjs/core';
+import { TypeOrmModule } from '@nestjs/typeorm';
+
+import { AuditController } from './audit.controller';
+import { AuditInterceptor } from './audit.interceptor';
+import { AuditLog } from './entities/audit-log.entity';
+import { AuditLogRepository } from './audit-log.repository';
+import { AuditService } from './audit.service';
+
+/**
+ * Backoffice audit trail.
+ *
+ * `AuditInterceptor` is bound through `APP_INTERCEPTOR`, so it applies to every
+ * route in the application without touching the 488 mutating handlers
+ * individually. Coverage therefore follows `AUDIT_ENDPOINTS`: a new route is
+ * audited as soon as it appears in that map, and unknown routes are skipped
+ * rather than recorded with an empty title.
+ *
+ * Global so other modules can inject `AuditService` to record domain events
+ * that do not map cleanly onto an HTTP request.
+ */
+@Global()
+@Module({
+  imports: [TypeOrmModule.forFeature([AuditLog])],
+  controllers: [AuditController],
+  providers: [
+    AuditLogRepository,
+    AuditService,
+    { provide: APP_INTERCEPTOR, useClass: AuditInterceptor },
+  ],
+  exports: [AuditService, AuditLogRepository],
+})
+export class AuditModule {}