fix: frontend reply syndication mapping and empty array cleanup

- Map platform to syndicator using service.name keys from isOwner API
- Add activitypub platform mapping (was completely missing)
- Remove empty mp-syndicate-to array for webmention replies (caused
  permanent no-op entries in syndication queue)

js/comments.js

@@ -137,14 +137,11 @@ document.addEventListener("alpine:init", () => {
             },
           };
 
-          // Only add syndication target for the matching platform
+          // Only add syndication target if one exists for the platform
           if (this.replyingTo.syndicateTo) {
             micropubBody.properties["mp-syndicate-to"] = [
               this.replyingTo.syndicateTo,
             ];
-          } else {
-            // IndieWeb webmention — no syndication, empty array
-            micropubBody.properties["mp-syndicate-to"] = [];
           }
 
           const res = await fetch("/micropub", {

js/webmentions.js

@@ -803,9 +803,12 @@
       btn.addEventListener('click', function() {
         var replyUrl = btn.dataset.replyUrl;
         var platform = btn.dataset.platform || 'webmention';
+        // Map detected platform to syndicator by service.name
+        var targets = ownerStore.syndicationTargets || {};
         var syndicateTo = null;
-        if (platform === 'bluesky') syndicateTo = ownerStore.syndicationTargets.bluesky || null;
+        if (platform === 'bluesky') syndicateTo = targets['Bluesky'] || null;
-        if (platform === 'mastodon') syndicateTo = ownerStore.syndicationTargets.mastodon || null;
+        if (platform === 'mastodon') syndicateTo = targets['Mastodon'] || null;
+        if (platform === 'activitypub') syndicateTo = targets['ActivityPub (Fediverse)'] || null;
 
         // Close any existing reply form
         closeActiveReplyForm();