Reads stdin, splits via CDC, deduplicates chunks against a sidecar
block store at <archive>.blocks/, writes a chunk-hash manifest at
<archive>. The reverse operation reads the manifest and reassembles
the byte stream from the block store.
Manifest format (magic UC2INGST) is a standalone container, not yet
unified with the master-block archive layout. Tar boundaries are not
preserved; the input is treated as an opaque byte stream. Follow-ups
filed for both.
Builds entirely on existing CDC + blockstore + merkle infrastructure.
No new compression or hashing primitives.
Tests cover small + 200 KB multichunk round-trip, idempotent dedup
(repeat ingest of the same data reports zero new chunks and exact
bytes_saved), empty stream, bad-magic rejection. Lint gate stays
green.
Closes fa0c7d4.
446158e855