Upgrade dependencies to latest compatible versions (#11)

* chore: update dependencies to latest versions

- restana ^5.0.0 -> ^6.0.0
- uuid ^11.0.5 -> ^14.0.0
- async-openssl 1.0.3 -> ^1.0.3
- axios ^1.7.9 -> ^1.16.1
- chai ^4.3.7 -> ^6.2.2
- jsonwebtoken ^9.0.2 -> ^9.0.3
- mocha ^11.1.0 -> ^11.7.6
- nyc ^17.1.0 -> ^18.0.0

* fix: resolve audit vulnerabilities and stabilize CI test startup

- add npm overrides for diff, serialize-javascript and uuid so
  transitive dev-dependency advisories are resolved (npm audit: 0 vulns)
- replace fixed 2800ms server-startup delay in tests with active
  health-endpoint polling to remove CI flakiness on slow runners

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Co-authored-by: Claude <noreply@anthropic.com>

Author: jkyberneees