[DEFER] Add end-to-end TLS/SSH interoperability smoke suite

[mark-e-deyoung]

Summary

Current tests validate TLS/SSH builders and key behavioral paths, but we still lack a dedicated end-to-end interoperability smoke suite that exercises real local handshake/session flows via CLI-driven scenarios.

Problem

Unit tests alone may miss integration regressions at runtime boundaries (cert loading, hostname checks, host-key checks, CLI orchestration).

Proposed scope

• Add local-loop E2E smoke suite for TLS and SSH interoperability.
• Cover success and failure paths (hostname mismatch, bad host key, mTLS requirement mismatch).
• Keep tests hermetic (ephemeral keys/certs, no persistent secrets).
• Integrate into CI with bounded runtime.

Acceptance criteria

• New E2E smoke suite runs in CI and is deterministic.
• Positive and negative protocol scenarios are asserted.
• Failures provide actionable diagnostics for humans/agents.

Category

DEFER