The docs named the `ai_model_price:update` permission but never said
which role holds it, and nothing anywhere explained that a price is
keyed by provider type and model, so every configured provider of that
type shares it. This names the Owner role, documents the keying and why
`openai-compat` cannot be priced, and repeats both in the CLI's
`--provider` descriptions and `update` help.
> [!NOTE]
> Initially generated by Claude Opus 5, modified and reviewed by
@ssncferreira
Susana Ferreira
d989ae36cd