Expand category docs and module APIs across the library.

Manual pass adds helpers (listChannels, taskCounts, openProposals), richer getStats with protocol fields, category README hubs, and tightened api.md for core, messaging, network, routing, supercomputer, and consensus modules.

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

messaging-pubsub/hyper-p2p-retained-messages/index.js

@@ -47,6 +47,10 @@ class HyperP2PRetainedMessages extends EventEmitter {
     return ok
   }
 
+  listChannels () { return [...this._store.keys()] }
+
+  hasChannel (channel) { return this._store.has(channel) }
+
   getStats () {
     return {
       ...this._stats,