b291214cd2
Split SiliconflowCN into its own [providers.siliconflow_cn] TOML section instead of silently ignoring [providers.siliconflow-CN] config. - ProvidersToml / ProvidersConfig: add siliconflow_cn field with serde alias - for_provider / for_provider_mut / provider_config_for: route SiliconflowCN to the new field - resolve_runtime_options_with_secrets: fallback siliconflow_cn → siliconflow for api_key / base_url / model when unset - deepseek_api_key: add config-file fallback for SiliconflowCn - provider_config_key: update metadata to "siliconflow_cn" - save_api_key_for: write SiliconflowCn keys to providers.siliconflow_cn - docs/PROVIDERS.md, config.example.toml, scripts/check-provider-registry.py