Cross-patient access via VAU header injection

HTTP header injection in fbeta GmbH ePA 3.x Integration before 1.3.0 allows remote authenticated users to alter VAU inner requests. In app/vau/VAUProtokoll.py, build_inner_header writes uri, host, Accept, Content-Type, Content-Length, USER_AGENT, and insurant_id directly into request lines and headers without neutralizing CRLF, letting attacker-controlled values append injected headers such as x-insurantid or Authorization. Exploitation requires authenticated control over one of those inputs, and the resulting header injection can expose another patient's records, cross the intended authentication or authorization context, or poison later requests through session-derived USER_AGENT data.