Add listKeys() and keyCount() helpers across modules (ninth pass).

Standardize key enumeration after size() on map- and registry-style modules, aliasing existing list* methods or primary store keys so callers can inspect occupancy without parsing snapshots.

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

media-streaming/hyper-p2p-stream-access-control/index.js

@@ -132,6 +132,14 @@ class HyperP2PStreamAccessControl extends EventEmitter {
     return this.snapshot().total
   }
 
+  listKeys () {
+    return [...this._tokens.keys()]
+  }
+
+  keyCount () {
+    return this.size()
+  }
+
   grantCapabilityBatch (entries) {
     if (!Array.isArray(entries)) throw new Error('entries array required')
     return entries.map((e) => this.grantCapability(e.streamId, e.subject, e.ttlMs))