Fix hook callback called multiple times in registerRoute

The Etherpad hook system expects cb() to be called exactly once per
hook invocation. In registerRoute, cb() was being called inside the
/p/*/feed route handler on every HTTP request (up to 5 times per
request depending on code path), in addition to the correct call at
the end of the hook. This could cause unpredictable behavior in the
hook system. Remove all cb() calls from inside route handlers, keeping
only the single call after all routes are registered.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: JohnMcLear

index.js

@@ -66,7 +66,6 @@ exports.registerRoute = (hookName, args, cb) => {
       if (!isPublished) { // If it's not already published and it's gone stale
         feeds[padId].lastEdited = message.lastEdited; // Add it to the timer object
       }
-      cb();
     } else {
       if (!feeds[padId].feed) { // If it's not already stored in memory
         console.debug('RSS Feed not already in memory so writing memory', feeds);
@@ -75,20 +74,16 @@ exports.registerRoute = (hookName, args, cb) => {
       } else {
         isPublished = true;
       }
-      cb();
     }
     if (!isPublished) {
       const pad = await padManager.getPad(padId);
       text = safe_tags(pad.text()).replace(/\n/g, '<br/>');
-    } else {
-      cb();
     }
 
     if (isPublished) {
       console.debug(`Sending RSS from memory for ${padId}`);
       res.contentType('rss');
       res.send(feeds[padId].feed);
-      cb();
     } else {
       console.debug(`Building RSS for ${padId}`);
       res.contentType('rss');
@@ -117,7 +112,6 @@ exports.registerRoute = (hookName, args, cb) => {
       args.content += '</rss>';
       feeds[padId].feed = args.content;
       res.send(args.content); // Send it to the requester
-      cb(); // Am I even called?
     }
   });
   cb();