Phase 2 completes the interface-to-protocol bridge and adds core types
that external crates depend on. The 8 tasks are organized into 5
generations with clear dependencies:
- Gen 1: StreamInterface/MessageInterface trait split (must go first)
- Gen 2: SshSession bridge, RawFraming impl, CredentialProvider (parallel)
- Gen 3: API keys in DynamicConfig (depends on CredentialProvider)
- Gen 4: ListenerConfig HTTP/DNS stubs + axum scaffold
- Gen 5: Review gate before Phase 3
Key design decisions:
- 2.4a/2.4b split: SecretStoreCredentialProvider deferred to Phase 3
- API keys (2.6) must land before axum scaffold (2.7)
- ListenerConfig (2.5) must land before axum scaffold (2.7)
- Gen 2 tasks are parallelizable (separate modules)
