.qcap writer/reader (ZIP/TAR+GZ) (#core-005)

[jvanulde]

Archive with manifest/payload/meta/signatures.

[edip-dev-01]

Addressed in fork commit edip-dev-01/q-cap@33659d9: writes .qcap ZIP archives with manifest.json, payload/, meta/, and signatures/manifest.sig.json, and reads them back in the CLI. Pending upstream merge: edip-dev-01@33659d9

[edip-dev-01]

Closed by merged PR #39: #39