fix(orders): delete NAS folder when order delete modal's checkbox is ticked

The order delete modal sends { delete_files }, but the route ignored the
body and deleteOrder never touched the NAS — so the project folder of an
order-spawned project always stayed on the share (the only way to delete
such a project is via its order, since deleteProject blocks order-linked
projects). Project delete (standalone projects) already worked.

- orders route: read delete_files from the body, pass to deleteOrder.
- orders.service deleteOrder(id, deleteFiles): select project_number and,
  after the DB transaction commits, best-effort deleteProjectFolder for
  each linked project when the flag is set. Non-fatal; idempotent.
- tests: NasFileManager.deleteProjectFolder coverage — removes by number
  prefix, no-op when absent, false when not mounted (158 -> 161 tests).

Bump version to 2.0.4.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "app-ts",
-  "version": "2.0.3",
+  "version": "2.0.4",
   "description": "",
   "main": "dist/server.js",
   "scripts": {