feat: use replyTargets config for platform-to-syndicator mapping

- Frontend now reads replyTargets from isOwner API to resolve which
  syndicator handles replies for each platform
- Build-time reply buttons get platform from URL heuristics as fallback
- enrichBuildTimeBadges upgrades to NodeInfo-resolved platform at runtime

_includes/components/webmentions.njk

@@ -153,9 +153,19 @@
             <div class="text-surface-700 dark:text-surface-300 prose dark:prose-invert prose-sm max-w-none">
               {{ reply.content.html | safe if reply.content.html else reply.content.text }}
             </div>
+            {% set replySource = reply['wm-source'] | default('', true) %}
+            {% set replyAuthorUrl = reply.author.url | default('', true) %}
+            {% set buildPlatform = 'webmention' %}
+            {% if 'bsky.app' in replyAuthorUrl or ('brid.gy/' in replySource and '/bluesky/' in replySource) %}
+              {% set buildPlatform = 'bluesky' %}
+            {% elif 'brid.gy/' in replySource and '/mastodon/' in replySource %}
+              {% set buildPlatform = 'mastodon' %}
+            {% elif 'fed.brid.gy' in replySource %}
+              {% set buildPlatform = 'activitypub' %}
+            {% endif %}
             <button class="wm-reply-btn hidden text-xs text-primary-600 dark:text-primary-400 hover:underline mt-2"
                     data-reply-url="{{ reply.url }}"
-                    data-platform="">
+                    data-platform="{{ buildPlatform }}">
               Reply
             </button>
           </div>

js/comments.js

@@ -12,6 +12,7 @@ document.addEventListener("alpine:init", () => {
     isOwner: false,
     profile: null,
     syndicationTargets: {},
+    replyTargets: {},
   });
 
   Alpine.data("commentsSection", (targetUrl) => ({
@@ -74,11 +75,13 @@ document.addEventListener("alpine:init", () => {
               photo: data.photo,
             };
             this.syndicationTargets = data.syndicationTargets || {};
+            this.replyTargets = data.replyTargets || {};
 
             // Also update global store for webmentions component
             Alpine.store("owner").isOwner = true;
             Alpine.store("owner").profile = this.ownerProfile;
             Alpine.store("owner").syndicationTargets = this.syndicationTargets;
+            Alpine.store("owner").replyTargets = this.replyTargets;
 
             // Note: owner:detected event is dispatched from init() after
             // this completes, so the Alpine store is populated before the event fires

js/webmentions.js

@@ -803,12 +803,11 @@
       btn.addEventListener('click', function() {
         var replyUrl = btn.dataset.replyUrl;
         var platform = btn.dataset.platform || 'webmention';
-        // Map detected platform to syndicator by service.name
+        // Map platform to syndicator via replyTargets config
         var targets = ownerStore.syndicationTargets || {};
-        var syndicateTo = null;
-        if (platform === 'bluesky') syndicateTo = targets['Bluesky'] || null;
-        if (platform === 'mastodon') syndicateTo = targets['Mastodon'] || null;
-        if (platform === 'activitypub') syndicateTo = targets['ActivityPub (Fediverse)'] || null;
+        var replyTargets = ownerStore.replyTargets || {};
+        var serviceName = replyTargets[platform] || null;
+        var syndicateTo = serviceName ? (targets[serviceName] || null) : null;
 
         // Close any existing reply form
         closeActiveReplyForm();