df0e97a168
MiniMax's /anthropic endpoint documents cache_control support (0.1x read pricing, 5-min TTL) for MiniMax-M2.7, M2.5, M2.1, M2. PR #12846 gated third-party Anthropic-wire caching on 'claude' in model name, which left MiniMax's own model family re-paying full input tokens every turn. Opt in explicitly via provider id (minimax / minimax-cn) or host match (api.minimax.io / api.minimaxi.com). Narrow allowlist mirroring the existing Qwen/Alibaba branch below; leaves room for a capability-based surface (ProviderConfig.supports_anthropic_cache) if a third provider needs it. Closes #17332