refactor: rename test-firewall-escape to firewall-escape and add 80% novelty requirement

- Renamed workflow from test-firewall-escape.md to firewall-escape.md
- Updated workflow name and description
- Added instruction for agent to prioritize new strategies (80% novel attempts)
- Agent now uses cache-memory to track and avoid repeating previous attempts

Co-authored-by: Mossaka <5447827+Mossaka@users.noreply.github.com>

Author: Copilot