Add size() cardinality helper across modules (eighth pass).

Standardize a size() method after isEmpty() on every module with clearAll(), delegating to domain counts or snapshot fields so callers can query occupancy without parsing snapshots.

Co-authored-by: Cursor <[email protected]>

state-crdts/hyper-p2p-crdt-version-vector/index.js

@@ -83,6 +83,10 @@ class HyperP2PCrdtVersionVector extends EventEmitter {
     return Object.keys(this.snapshot()).length === 0
   }
 
+  size () {
+    return Object.keys(this.snapshot()).length
+  }
+
   get (peer) {
     return this._clock.get(assertPeer(peer)) || 0
   }