build(deps-dev): bump typescript from 5.8.3 to 5.9.2 in /backend

Bumps [typescript](https://github.com/microsoft/TypeScript) from 5.8.3 to 5.9.2.
- [Release notes](https://github.com/microsoft/TypeScript/releases)
- [Changelog](https://github.com/microsoft/TypeScript/blob/main/azure-pipelines.release-publish.yml)
- [Commits](microsoft/TypeScript@v5.8.3...v5.9.2)

---
updated-dependencies:
- dependency-name: typescript
  dependency-version: 5.9.2
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

backend/package-lock.json

@@ -40,7 +40,7 @@
     "jest": "^30.0.5",
     "ts-jest": "^29.4.0",
     "tsx": "^4.20.3",
-    "typescript": "^5.8.3"
+    "typescript": "^5.9.2"
   },
   "dependencies": {
     "@fastify/type-provider-typebox": "^5.2.0",