instructions/dev: Konverter-Vergleich – eigene Ableitung gegen Referenzwerkzeuge am privaten Korpus, sieben Maße, Grundlinie nur bewusst fortgeschrieben (#233); 10.1.0-beta.3

Files changed:
- CHANGES.md
- VERSION
- docs/dev/development.md
- instructions/dev/converter-comparison.md
- instructions/dev/stack-mode.md
- instructions/dev/testing-conventions.md

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SnAJ7Z3CpVD3PRbN73QtU2

instructions/dev/testing-conventions.md

@@ -193,7 +193,9 @@ cloned into the gitignored `testfiles/` ([dev-setup.md](dev-setup.md) step 6) an
 checkout's `tools/.venv` by the `converters` workflow. A new file for the corpus is a case for
 that harness, not a fixture here; the synthetic filter tests (`test_raw_derive.py`,
 `test_raw_derive_binary.py`) stay and are what the suite relies on. The harness borrows this
-suite's `conftest.py`, so a change to a fixture there reaches it too.
+suite's `conftest.py`, so a change to a fixture there reaches it too. Whether a derivation is
+*good* - right markings, no noise, nothing a reference tool reads better - is no test at all but
+a measured comparison: [converter-comparison.md](converter-comparison.md).
 
 This file says nothing about what to test - the test/review
 expectations for a stack change are the local checks in [publish-and-ci.md](publish-and-ci.md)