CDN-298: The Replay Packet

CDN-298 hardens the CDN-297 encounter ledger into a machine-readable replay packet standard. The required packet blocks are identity, time grid, state vectors, radial/tangential decomposition, residuals, covariance, systematics, and kernel provenance. The required synchronized series are t_s, v_r, v_t, Delta, and sigma_Delta. A frozen seven-packet validation assay gives two analysis-ready packets, one tangential null, three quarantines, and one high-drive wall tracer. Speed-only, sign-ambiguous, covariance-free, or non-replayable claims do not count as clean GCFT Channel-B flyby evidence.