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-web/backoffice/src/lib/permissions.ts

@@ -105,6 +105,7 @@ export const FREIGHT_PERMS = {
     dispatch: "edr_freight_app:train_scheduling:dispatch",
     markPaid: "edr_freight_app:train_scheduling:mark_paid",
     expireBooking: "edr_freight_app:train_scheduling:expire_booking",
+    editTrainNumber: "edr_freight_app:train_scheduling:edit_train_number",
   },
   fleet: {
     view: "edr_freight_app:fleet:view",
@@ -311,6 +312,13 @@ export const FREIGHT_PERMS = {
     cancel: "edr_freight_app:warehouse_fee_invoices:cancel",
     pay: "edr_freight_app:warehouse_fee_invoices:pay",
   },
+  /**
+   * Audit trail. View-only — the API exposes no write routes for audit rows,
+   * so there is no manage/delete counterpart to grant.
+   */
+  auditLog: {
+    view: "edr_freight_app:audit_log:view",
+  },
   settings: {
     fileUpload: {
       view: "edr_freight_app:settings:file_upload:view",