graph-store: if there is no hash in added node, replace signatures with ~, otherwise check validity of signatures
=/ =validated-portion:store
[parent-hash author.p time-sent.p contents.p]
=/ =hash:store `@ux`(sham validated-portion)
- ?~ hash.p node
+ ?~ hash.p node(signatures.post *signatures:store)
+ ~| "signatures do not match the calculated hash"
+ ?> (are-signatures-valid:sigs signatures.p hash now.bowl)
~| "hash of post does not match calculated hash"
?> =(hash u.hash.p)
node
