nx_algo_registry_migrate.nx

nx_algo_registry_migrate.nx -- migrate specs/algo_registry/<algo>/meta.json (the 3,282 JSON algorithm cards) into ONE sovereign seg_store (knowledge/store/algo-registry-), key = algo name, value = meta.json bytes (byte-faithful, content-addressed). The cards total ~1.4MB, so the writer is sized to hold them all in a SINGLE segment -> one commit (no multi-commit segid collision). Self-verifies: re-opens the store, round-trips a known card byte-for-byte + checks the count key. This is the "get the JSON onto the nishi ecosystem" win; repointing the consumer (nx_bundle_gen) + retiring the derived JSON is the NEXT (gated) step. expect_exit: 0 license_tier: ORIGINAL