feat: add key management and provider keypool (# new feature)

Preserve gateway model identity in Anthropic responses (#1270)

Make ProviderModelInfo the sole model-catalog contract (#1222)

Make reasoning policy provider-neutral and client-aware (#1148)

Consolidate OpenAI-compatible provider adapters (#1069)

Make response stream lifetimes explicit (#1060)

Canonicalize provider failure and retry ownership (#1046)

Introduce a typed application boundary for provider execution (#1045)

Move protocol models to their protocol owners (#1044)

Move runtime packages under src namespace (#1029)