feat(wagons): audited maintenance/availability toggle

apps/edr-freight-api/src/migrations/3310000000000-WagonStatusLogs.ts

@@ -0,0 +1,32 @@
+import { MigrationInterface, QueryRunner } from 'typeorm';
+
+/**
+ * Audit trail for wagon status flips (Available ⇄ Maintenance and any other
+ * bulk-status change): who moved which wagon from what to what, when, and why.
+ * Written inside the same transaction as the status update itself.
+ */
+export class WagonStatusLogs3310000000000 implements MigrationInterface {
+  public async up(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`
+      CREATE TABLE IF NOT EXISTS freight.wagon_status_logs (
+        id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
+        wagon_id uuid NOT NULL REFERENCES freight.wagons(id),
+        from_status varchar(30) NOT NULL,
+        to_status varchar(30) NOT NULL,
+        changed_by_user_id uuid,
+        note text,
+        created_at timestamptz NOT NULL DEFAULT now(),
+        updated_at timestamptz NOT NULL DEFAULT now(),
+        deleted_at timestamptz
+      )
+    `);
+    await queryRunner.query(`
+      CREATE INDEX IF NOT EXISTS idx_wagon_status_logs_wagon
+        ON freight.wagon_status_logs (wagon_id, created_at DESC)
+    `);
+  }
+
+  public async down(queryRunner: QueryRunner): Promise<void> {
+    await queryRunner.query(`DROP TABLE IF EXISTS freight.wagon_status_logs`);
+  }
+}