Optimize secret-digger-copilot: remove unused tools, condense prompt, add emergency exit rule

- Remove github toolsets and edit tool from shared/secret-audit.md frontmatter
- Add Emergency Exit Rule to prevent near-empty response retry loops
- Condense technique examples from 8-bullet to 1-line-with-examples per item (~3KB savings)
- Recompile secret-digger-copilot.lock.yml with gh-aw v0.66.1
- Post-process all lock files

Note: max-turns:4 not added - copilot engine does not support max-turns

Agent-Logs-Url: https://github.com/github/gh-aw-firewall/sessions/5a262b3d-b3ef-4910-9c45-598c3d00ef31

Co-authored-by: lpcox <15877973+lpcox@users.noreply.github.com>

Author: Copilot