[.ai doc] Refine .ai attention-mask and component-mutation guidance (#13982)
Refine .ai attention-mask and component-mutation guidance from a PR review
- models.md: clarify padding-mask bullet — pass None when padding is
uniform (mask.all()) or when the model is trained to tolerate padding
without a mask
- pipelines.md: add gotcha #7 — don't mutate registered component state
per call; prefer an already-prepared component, otherwise snapshot and
restore (PAG pattern)
Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>