v0.43

Read more at: https://omd.consol.de/blog/2026/05/22/snclient-0.43-was-released/

Changes:

- *DEPRECATION NOTICE* linux agent runs now as unprivileged snclient user
- update node exporter to 1.11.1
- update windows exporter to 0.31.6
- use linux capabilities for check_omd
- update golang build chain to 1.26.3
- make listener errors fatal during startup
- check_tcp: make hostname mandatory
- check_tcp: critical defaults to 10s
- check_tcp: add time performance data
- check_http: add certificate checks and redirect support
- add /api/v1/admin/log/level rest endpoint to change log level
- add /api/v1/admin/log/file rest endpoint to retrieve log file
- check_ssh: add new check_ssh to test ssh server