converters: Testkorpus und Harness ziehen nach torben/chemenu-testfiles, Workflow Converters mit Pfad-Trigger, Release-Gate (#232); 10.1.0-beta.2

Files changed:
- .gitattributes
- .gitea/workflows/converters.yml
- .gitea/workflows/release.yml
- .gitignore
- CHANGES.md
- VERSION
- docs/dev/development.md
- instructions/dev/dev-setup.md
- instructions/dev/publish-and-ci.md
- instructions/dev/testing-conventions.md
- testfiles/README.md
- testfiles/mail/github-outlook.msg
- testfiles/mail/github-roundcube.eml
- testfiles/mail/gog-outlook.msg
- testfiles/mail/gog-roundcube.eml
- testfiles/mail/gog-roundcube.eml.expect
- testfiles/mail/tldr-outlook.msg
- testfiles/mail/tldr-roundcube.eml
- testfiles/office/excel-artificial.xlsx
- testfiles/office/excel-business.xlsx
- testfiles/office/excel-business.xlsx.expect
- testfiles/office/excel-science.xlsx
- testfiles/office/pptx-baseline.pptx
- testfiles/office/pptx-master.pptx
- testfiles/office/pptx-objects.pptx
- testfiles/office/word-complex.docx
- testfiles/office/word-simple.docx
- testfiles/pdf/einstein-dissertation.pdf
- testfiles/pdf/ifg.pdf
- testfiles/pdf/nist-ai-rmf.pdf
- testfiles/pdf/nist-ssdf-genai.pdf
- testfiles/zip/archive.zip
- tools/chemenu/tests/test_raw_derive_testfiles.py

Co-Authored-By: Claude Code <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

.gitignore

@@ -192,6 +192,12 @@ npm-debug.log*
 # anchored back open by the content backstop below, same as `incoming/`.
 /quarantine/
 
+# The private test corpus and converter harness (Gitea #232): a clone of
+# torben/chemenu-testfiles, made by hand (instructions/dev/dev-setup.md) and run by
+# .gitea/workflows/converters.yml. It is its own repository, so this one never tracks it; a clone
+# without access simply has no such directory, and nothing in the stack's suite needs it.
+/testfiles/
+
 # Content backstop - keep this block last. Nothing under raw/, kb/, work/ or sites/ may
 # be excluded by a pattern above; see the header note for why directory patterns
 # still have to be anchored rather than relying on these negations.