Add train deactivation feature and import train number management

- Introduced DEACTIVATED status for trains, allowing staff to park trains indefinitely.
- Implemented methods to deactivate and reactivate trains in the TrainBuilderService.
- Added UI components for train deactivation and reactivation in TrainBuilderDetailPage.
- Created a dropdown setting for admin-managed import train numbers, with corresponding migrations.
- Updated yard code length to accommodate soft-delete suffix.
- Enhanced train status handling to include DEACTIVATED state.

apps/edr-freight-api/src/modules/trains/train-builder.service.ts

@@ -153,6 +153,38 @@ export class TrainBuilderService {
     };
   }
 
+  /**
+   * Run numbers already claimed by live (non-deleted) trains, split by
+   * direction. Legacy single `train_number` values are sorted into a side by
+   * parity (even = import, odd = export) so the pickers can grey them out too.
+   */
+  async usedTrainNumbers() {
+    const rows: {
+      import_train_number: string | null;
+      export_train_number: string | null;
+      train_number: string | null;
+    }[] = await this.dataSource.query(
+      `SELECT import_train_number, export_train_number, train_number
+         FROM freight.trains
+        WHERE deleted_at IS NULL`,
+    );
+
+    const importTrainNumbers = new Set<string>();
+    const exportTrainNumbers = new Set<string>();
+    for (const row of rows) {
+      if (row.import_train_number) importTrainNumbers.add(row.import_train_number);
+      if (row.export_train_number) exportTrainNumbers.add(row.export_train_number);
+      const legacy = row.train_number?.trim();
+      if (legacy && /^\d+$/.test(legacy)) {
+        (Number(legacy) % 2 === 0 ? importTrainNumbers : exportTrainNumbers).add(legacy);
+      }
+    }
+    return {
+      importTrainNumbers: [...importTrainNumbers].sort(),
+      exportTrainNumbers: [...exportTrainNumbers].sort(),
+    };
+  }
+
   /**
    * One ACTIVE schedule per train for the page (prefer the DISPATCHED run,
    * else the earliest upcoming departure) — feeds the list's direction tint
@@ -532,6 +564,50 @@ export class TrainBuilderService {
     return this.getComposition(id);
   }
 
+  /**
+   * Park the train indefinitely (status DEACTIVATED). Blocked while it still
+   * has a live (DRAFT/SCHEDULED/DISPATCHED) schedule. The consist stays
+   * coupled; like UNDER_MAINTENANCE / OUT_OF_SERVICE the flag is staff-owned —
+   * the scheduler never overwrites it and refuses the train for new schedules.
+   */
+  async deactivate(id: string) {
+    await this.dataSource.transaction(async (manager) => {
+      const train = await manager.getRepository(Train).findOne({ where: { id } });
+      if (!train) throw new NotFoundException(`Train ${id} not found`);
+      if (train.status === Freight.TrainStatus.Deactivated) return;
+      const active: { count: string }[] = await manager.query(
+        `SELECT COUNT(*)::text AS count
+           FROM freight.train_schedules ts
+           JOIN freight.train_sets tset ON tset.id = ts.train_set_id
+          WHERE tset.train_id = $1
+            AND ts.deleted_at IS NULL
+            AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')`,
+        [id],
+      );
+      if (Number(active[0]?.count ?? 0) > 0) {
+        throw new ConflictException(
+          'Train has active schedules; cancel them before deactivating the train',
+        );
+      }
+      await manager
+        .getRepository(Train)
+        .update(id, { status: Freight.TrainStatus.Deactivated });
+    });
+    return this.getComposition(id);
+  }
+
+  /** Reactivate a DEACTIVATED train back to AVAILABLE so it can be scheduled again. */
+  async activate(id: string) {
+    const train = await this.dataSource.getRepository(Train).findOne({ where: { id } });
+    if (!train) throw new NotFoundException(`Train ${id} not found`);
+    if (train.status === Freight.TrainStatus.Deactivated) {
+      await this.dataSource
+        .getRepository(Train)
+        .update(id, { status: Freight.TrainStatus.Available });
+    }
+    return this.getComposition(id);
+  }
+
   /** Disband the train: release wagons and locomotives, then delete it. */
   async disband(id: string): Promise<void> {
     await this.dataSource.transaction(async (manager) => {