0d8b2cdb3f
- Add helmet for secure HTTP response headers. - Add express-rate-limit: 60 req/min general, 20 req/min on LLM endpoints. - Restrict CORS to localhost origins in dev, CORS_ORIGIN env var in prod. - Cap request body at 16kb. - Add sanitizeText() to strip control chars on all string inputs. - Add isValidStandardId() regex guard on :id param and standard_id fields. - All route handlers use sanitized values; no raw req.body/req.query access.