Release 0.7.8: Euro-Office oracle and packaged dispatcher fix

[BramAlkema]

Summary

• add the Euro-Office 9.3.3 / Nextcloud connector 11.0.1 capability model and authenticated conversion oracle
• record the first live six-file Euro-Office conversion baseline with explicit browser-editor evidence limits
• include tools.oracle in built wheels so every openxml-audit-oracle engine works from PyPI
• smoke-test all packaged oracle engines in the tag-triggered release workflow
• release as 0.7.8

Verification

• PYTHONPATH=src pytest -q — 751 passed, 9 skipped
• changed-file Ruff format/lint — passed
• strict mypy for the new Euro-Office library — passed
• actionlint .github/workflows/release.yml — passed
• isolated sdist-to-wheel build and Twine checks — passed
• clean dependency-isolated wheel install, pip check, metadata assertions, and all seven dispatcher --help paths — passed

Live evidence

The Opus95 endpoint was healthy and reported 9.3.1.37, which is recorded separately from upstream 9.3.3. DOCX/XLSX conversion was validator-clean; the committed baseline preserves the PPTX source-finding distinction, ODF target findings, and ODP converter failure without claiming browser edit/save coverage.