fable-mode: re-scope for Claude 5 and add a guard-friction section

[marcelolafleur]

The fable-mode skill was written for weaker models: most of its five-gate prose is native behavior on Claude 5, and repeating it gets in the way. Separately, benign work — security fixes on our own repos, mortality data for the OG models — keeps tripping the Fable-tier safety classifiers.

Changes:

• Compress the generic five-gate discipline to a skeleton; keep the environment ritual and the orchestration/routing table in full (the incident-derived parts).
• Split the full gate prose into references/full-discipline.md — mandatory Read for sub-frontier models (Sonnet/Haiku), on-failure fallback for frontier ones.
• Add a "Guard friction" section: make benign work legible to the safety classifiers — context-forward framing, neutral verbs, workspace-content awareness, a when-a-flag-fires protocol — with an explicit never-evade list.

Tested: installed locally and driving real sessions; guard-friction guidance sourced from Anthropic's docs and documented claude-code issues.