Add Access routes to Swagger specification

[magush27]

Add all Cboard Access endpoints and schema definitions to the Swagger/OpenAPI specification.

File: api/swagger/swagger.yaml

Tasks:

1. Add public paths:

   • /access/clients - GET getClients
   • /access/{code} - GET getAccessBoard

2. Add admin paths with Bearer security:

   • /admin/access-clients - POST createAccessClient, GET listAccessClients
   • /admin/access-clients/{code} - PUT updateAccessClient
   • /admin/access-clients/{code}/stats - GET getAccessClientStats

3. Add definitions:

   • AccessClientCreate
   • AccessClientUpdate
   • AccessClientResponse
   • AccessClientsListResponse
   • AccessClientsAdminListResponse
   • AccessBoardResponse