chore(deps): bump zod from 3.25.51 to 3.25.75 in /backend

Bumps [zod](https://github.com/colinhacks/zod) from 3.25.51 to 3.25.75.
- [Release notes](https://github.com/colinhacks/zod/releases)
- [Commits](colinhacks/zod@v3.25.51...v3.25.75)

---
updated-dependencies:
- dependency-name: zod
  dependency-version: 3.25.75
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

Author: dependabot[bot]

backend/package-lock.json

@@ -84,7 +84,7 @@
     "typeorm": "^0.3.25",
     "undici": "^7.11.0",
     "winston": "^3.17.0",
-    "zod": "3.25.51"
+    "zod": "3.25.75"
   },
   "devDependencies": {
     "@eslint/compat": "1.2.9",