chore: drop scratch detail.html.twig override

The template was a global EasyAdmin override that rendered a hardcoded
"Notes" fieldset with placeholder text on every entity's detail page.
Clearly leftover from local exploration; if notes belong on the
SecurityContract detail, add the field via configureFields() instead.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: turegjorup