SAFETY-97: point test_safety97 at MUTATION.md; record the DC-entity option

test_bytecode requires every suite to name MUTATION.md (CI run 1158).
DECISIONS: why the integration's DC battery power entity is not the fix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_019DBUfvndgHwaV339Fvd2gr

goodwe_controller/test_safety97.py

@@ -16,7 +16,7 @@ DECISIONS/SAFETY-97-idle-offset.md.
 3. Learning: not while refusing or asked, bounded, restored, follows drift.
 4. The rules at their edges.
 
-Mutations (purged copies) are listed in the pull request.
+Mutations (MUTATION.md, purged copies) are listed in the pull request.
 """
 
 import logging