Exclude native TCP from the coordinated stable baseline

[RobLe3]

Summary

• make supported HTTP the coordinated stable qualification target
• classify plaintext native TCP as explicit development-only and exclude it from stable/production claims
• forbid treating HTTPS proxy/tunnel evidence as native TLS evidence
• retain cross-SDK byte-vector conformance without overstating production readiness
• add the canonical native fixture checker to the profile contract
• classify the Rust Directory discovery-scale test intent and refresh integrity projections

Validation

• complete profile fixture contract passed
• generated implementation and release-closure checks passed
• native Rust/Python/TypeScript framing vectors passed with canonical digest 02cc7bfbd3c238191ca3961aa03d09f143a51a43397e056d496977e5a9bf0471

No ratification, release or deployment is part of this PR.