Add typed crsql changes extraction

README.md

@@ -88,7 +88,8 @@ The bootstrap implementation provides:
 - local filesystem CAS commands: `add`, `get`, `hash`, `has`, `pin`, `unpin`,
   `cleanup`, `list`
 - local DB resource registration: `geth db add <name> <path>` and
-  `geth db status <name>` with schema and `crsql_changes` metadata
+  `geth db status <name>` with schema and `crsql_changes` metadata; the DB
+  crate can extract typed local `crsql_changes` batches for future sync
 - local SQLite-backed KV commands: `geth kv create/set/get`
 - local JSON document commands: `geth document create/status/set/get`
 - local daemon-lifetime pubsub snapshots: `geth pubsub pub/sub`