Scope per-repo commit attribution rules to project memory

When a user forbids agent Co-Authored-By trailers for one repo only, store the rule in the project-scoped memory directory (Claude Code keys it by working-directory path), not global CLAUDE.md, and state explicitly in the note that attribution is fine in other projects. The harness system-reminder keeps asking for attribution lines; the user's memory rule takes precedence, so the note should say it overrides that reminder. Users may phrase this as 'no coauthoring is fine, just not for this project', which reads ambiguously: confirm the scope instead of making the rule global.