Add English documentation

[Dedsec-Art]

What changed

• added complete English versions of the project overview, user guide, changelog, contribution guide, security policy, support guide, and Code of Conduct
• added clear German/English language switches while keeping all German documentation
• made issue forms, the pull request template, and generated release-note categories bilingual
• updated private vulnerability reporting links and clarified the stream-preserving 1:1 guarantee in German and English
• added contract tests for English documentation, cross-language links, private security reporting, and privacy warnings

Why

Ultra is now public, so international users should be able to understand, install, evaluate, and contribute to the project without losing the existing German documentation.

User and developer impact

Documentation and GitHub community surfaces become bilingual. The application interface itself remains German and is explicitly described as such. Runtime behavior is unchanged.

Verification

• python tools\check_public_tree.py — PUBLIC_AUDIT_OK files=203
• python -m unittest ripper_py.tests.test_community_contract — 7/7 passed
• python -m ripper_py.tests.run_all — 1093/1093 passed
• all 7 GitHub YAML files parsed successfully
• all relative links across the 14 German/English core documents were verified
• independent translation and security review found no blockers