feat(posts): Add swarm reply tracking and thread visualization

- Add swarm reply metadata fields (swarmReplyToId, swarmReplyToContent, swarmReplyToAuthor) to posts table for tracking replies to federated posts
- Extend swarmReplyTo schema to include optional content and author information for context preservation
- Build synthetic replyTo objects from swarm reply metadata to unify local and federated reply handling
- Include media in replyTo relations across all post queries for complete reply context
- Add thread container styling with visual line connector between parent and child posts
- Implement thread parent display mode with reduced opacity and hidden actions for context
- Add showThread and isThreadParent props to PostCard for flexible thread rendering
- Enable inline parent post visualization when viewing post details to show conversation context

src/app/globals.css

@@ -270,6 +270,37 @@ a.btn-primary:visited {
   overflow-y: auto;
 }
 
+/* Thread Container */
+.thread-container {
+  position: relative;
+}
+
+.thread-container .post {
+  border-bottom: none;
+  padding-bottom: 8px;
+}
+
+.thread-line {
+  position: absolute;
+  left: 36px;
+  top: 56px;
+  bottom: 0;
+  width: 2px;
+  background: var(--border);
+}
+
+.post.thread-parent {
+  opacity: 0.85;
+}
+
+.post.thread-parent .post-actions {
+  display: none;
+}
+
+.post.thread-parent .post-content {
+  font-size: 14px;
+}
+
 /* Post */
 .post {
   padding: 16px;