Removed Circular includes

this change ensures that headers include what they use, rather than relying on include order, which makes the codebase more robust against formatting changes and refactoring.

find include src tests -name '*.h'
-exec sh -c 'echo "#include "$1"" | cc -Werror -I. -Iinclude -c - >/dev/null' sh {} ;

to get all the files that needed changes in their headers

libssh_version.h exists because when you compile headers without running CMake, this file does not exist — so headers that are actually correct will fail.

Closes #350

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
• The project pipelines timeout is extended at least to 2 hours.

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