feat(journey-client): wellknown-endpoint-config-support

Re-implement well known configuration and abstract into reusable package
  - Remove internal re-export file (wellknown.api.ts)
  - Import directly from source packages in internal modules
  - Keep consumer-facing exports in types.ts as the single public API
  - Add IPv6 localhost comment explaining design decision
  - Remove redundant inline comments (JSDoc is sufficient) [Self-Healing CI Rerun]

Author: nx-cloud[bot]