Don't copy the bans into every repo

The failure mode is a style guide pasted into six repos, then edited in one of them on a Thursday.

Keep one core. A project overlay adds pronouns, terms that pass here, and protected lines. It does not restate the bans. Genre files do the same: point at core, then only what that surface adds.

If you copy core.md into the repo so the agent has it locally, you have started a second canon. Six months later nobody knows which file wins.