build(deps): bump react-router from 7.15.1 to 7.18.2 in /frontend

Closes four open Dependabot advisories, all patched in 7.18.0:
- Unauthenticated DoS via inefficient route matching
- Open redirect via backslash in <Link>/useNavigate (CVE-2025-68470 bypass)
- Arbitrary constructor injection in deserializeErrors()
- RSCErrorHandler missing protocol validation (XSS)

Supersedes #726, which proposed the 8.3.0 major. v8 is not required for
any of these fixes and would additionally impose Node >=22.22.0,
React >=19.2.7, ESM-only distribution and an ES2022 target.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: undera

frontend/package-lock.json

@@ -41,7 +41,7 @@
     "react-icons": "^5.5.0",
     "react-intersection-observer": "^10.0.3",
     "react-modern-drawer": "^1.4.0",
-    "react-router": "^7.13.0",
+    "react-router": "^7.18.2",
     "react-select": "^5.10.2",
     "swagger-ui-react": "^5.31.2",
     "uuid": "^14.0.0"