Fix Leaking Internal Error Messages to Client

[sahare77]

Resolves #1001

Description
This pull request prevents internal error messages and stack traces from leaking to the client in production.

• A global error handler middleware was added to \server.js\ to catch unhandled errors and return a generic 'Internal Server Error' response in production.
• Replaced explicit \error.message\ disclosures in
  otesSummaryRoutes.js,
  otesSummaryController.js, \�iController.js, and
  esumeController.js\ with generic client-facing messages.
• Kept \console.error\ logging for server-side debugging.