chore(deps): bump react-router-dom to ^7.15.0 (fixes 4 HIGH react-router CVEs)

Trivy flagged react-router 7.13.0 (transitive via react-router-dom) with 4 HIGH CVEs: CVE-2026-33245 (XSS in RSC redirect), -34077 (DoS), -42211 (turbo-stream arbitrary constructor), -42342 (DoS via unbounded path expansion). All fixed by <=7.15.0; bumping the floor resolves react-router to 7.17.0, clearing all four.

Validated: frontend typecheck clean, 13 vitest tests pass, build succeeds. Dependency bump only, no code changes.

Author: DevanshuNEU

frontend/bun.lock

@@ -45,7 +45,7 @@
     "next-themes": "^0.4.6",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
-    "react-router-dom": "^7.12.0",
+    "react-router-dom": "^7.15.0",
     "react-syntax-highlighter": "^16.1.0",
     "sigma": "^3.0.2",
     "sonner": "^2.0.7",