CborCheckpointStoreAdapter owns general CRDT serialization

[flyingrobots]

Migrated from Method backlog

GitHub Issues are now the live work tracker. Repository docs remain Method evidence.

Field	Value
Source backlog	docs/method/backlog/bad-code/SUB_cbor-checkpoint-crdt-serialization.md
Archived source	docs/archive/backlog/github-issue-migration-2026-06-01/docs/method/backlog/bad-code/SUB_cbor-checkpoint-crdt-serialization.md
Original lane	bad-code
Original id	SUB_cbor-checkpoint-crdt-serialization
Original legend	SUB
Original feature	trie-state-storage
Original release home	v17.0.0

Original backlog card

CborCheckpointStoreAdapter owns general CRDT serialization

Effort: M

CborCheckpointStoreAdapter.js (~366 LOC) carries full CRDT
serialization logic for LWW registers, ORSet entries, edge birth
events, and property maps. This serialization is general-purpose
CRDT encoding, not checkpoint-specific.

What's wrong

• S concern: The adapter should orchestrate read/write against
  the blob port, not own the full serialize/deserialize for every
  CRDT type.
• If another adapter needs CRDT serialization (e.g., a future
  snapshot export), the logic would be duplicated.

Suggested fix

Extract CRDT serialization to a CrdtCodec or StateCodec module
in src/infrastructure/codecs/. The checkpoint adapter calls it
for encode/decode, then writes blobs.