Resolve Sonar findings of June 2026

[redcatbear]

Situation

2026-06-02 Sonar reports 375 findings. Those were collected over the years because Sonar gained new rules over time, so that previously acceptable code is now marked.

https://sonarcloud.io/project/issues?issueStatuses=OPEN&id=org.itsallcode.openfasttrace%3Aopenfasttrace-root

Acceptance Criteria

1. All Critical (0), High (31) and Medium (70) are closed
2. (optional) All Low (262) and Info (12) are closed