mbedtls + messages patches from ML

Running CI on patches received on mailing list from Daniel

• https://archive.libssh.org/libssh/2026-08/0000000.html
• https://archive.libssh.org/libssh/2026-08/0000001.html
• https://archive.libssh.org/libssh/2026-08/0000002.html
• https://archive.libssh.org/libssh/2026-08/0000003.html

Checklist

• Commits have Signed-off-by: with name/author being identical to the commit author
• Code modified for feature
• Test suite updated with functionality tests
• Test suite updated with negative tests
• Documentation updated

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTING.md
• This feature/change has adequate documentation added
• No obvious mistakes in the code