add permanent purge functionality for wagons and routes

- Implemented a  method in  to permanently delete wagons without history.
- Added corresponding permissions for hard delete actions in .
- Updated the UI components to include purge actions, ensuring they are only available to users with the appropriate permissions.
- Created modals for confirming permanent deletions in  and .
- Enhanced API services to handle purge requests for locomotives, wagons, and routes.
- Added tests for the purge functionality in both  and  services to ensure proper behavior and error handling.

apps/edr-freight-api/src/modules/wagons/wagons.service.ts

@@ -212,6 +212,75 @@ export class WagonsService {
     await this.wagonRepo.softRemove(wagon);
   }
 
+  /**
+   * Permanently purge a wagon — irreversible, and only for rows that carry no
+   * history: a mistyped or duplicated entry someone wants gone for good.
+   *
+   * `wagon_movements` cascades on delete, so a wagon with movements would take
+   * its ledger history down with it. Rather than allow that, every reference is
+   * checked first and the purge is refused if any exist — soft delete (`remove`)
+   * stays the answer for a wagon that has actually been used.
+   *
+   * Soft-deleted wagons are purgeable, so `withDeleted` is used to find them.
+   */
+  async purge(id: string): Promise<void> {
+    const wagon = await this.wagonRepo.findOne({
+      where: { id },
+      withDeleted: true,
+    });
+    if (!wagon) {
+      throw new NotFoundException(`Wagon ${id} not found`);
+    }
+
+    if (wagon.trainId != null) {
+      throw new ConflictException(
+        `Wagon ${wagon.wagonNumber} is coupled to a train; detach it via train-builder before deleting it permanently`,
+      );
+    }
+    if (await this.isWagonPinnedToLiveSchedule(id)) {
+      throw new ConflictException(
+        `Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be deleted permanently`,
+      );
+    }
+
+    // Each of these would either lose history (movements cascade) or silently
+    // blank a live reference (containers / train-set slots are SET NULL).
+    const blockers: string[] = [];
+    const [movements, containers, trainSetSlots] = await Promise.all([
+      this.dataSource.query(
+        `SELECT count(*)::int AS count FROM freight.wagon_movements WHERE wagon_id = $1`,
+        [id],
+      ),
+      this.dataSource.query(
+        `SELECT count(*)::int AS count FROM freight.containers WHERE wagon_id = $1`,
+        [id],
+      ),
+      this.dataSource.query(
+        `SELECT count(*)::int AS count FROM freight.train_set_wagons WHERE physical_wagon_id = $1`,
+        [id],
+      ),
+    ]);
+    if (movements[0]?.count > 0) {
+      blockers.push(`${movements[0].count} movement record(s)`);
+    }
+    if (containers[0]?.count > 0) {
+      blockers.push(`${containers[0].count} container(s)`);
+    }
+    if (trainSetSlots[0]?.count > 0) {
+      blockers.push(`${trainSetSlots[0].count} train-set slot(s)`);
+    }
+
+    if (blockers.length > 0) {
+      throw new ConflictException(
+        `Wagon ${wagon.wagonNumber} cannot be permanently deleted — it still has ${blockers.join(
+          ', ',
+        )}. Delete it normally instead, which keeps the history intact.`,
+      );
+    }
+
+    await this.wagonRepo.remove(wagon);
+  }
+
   /**
    * A wagon is busy when any live (DRAFT/SCHEDULED/DISPATCHED) schedule pins it
    * to one of its slots — schedule occupancy lives on TrainSetWagon rows, not