Add delay between thread posts to ensure proper indexing

- Add 0.5s sleep between posts in create_thread
- Prevents 'Parent post not found' errors
- Ensures each post is indexed before creating replies

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

examples/atproto_mcp/src/atproto_mcp/_atproto/_posts.py

@@ -1,5 +1,6 @@
 """Unified posting functionality."""
 
+import time
 from datetime import datetime
 
 from atproto import models
@@ -334,6 +335,9 @@ def create_thread(posts: list[ThreadPost]) -> ThreadResult:
                 root_uri = result["uri"]
                 parent_uri = root_uri
                 post_uris.append(root_uri)
+
+                # Small delay to ensure post is indexed
+                time.sleep(0.5)
             else:
                 # Subsequent posts reply to the previous one
                 result = create_post(
@@ -359,6 +363,10 @@ def create_thread(posts: list[ThreadPost]) -> ThreadResult:
                 parent_uri = result["uri"]
                 post_uris.append(parent_uri)
 
+                # Small delay between posts
+                if i < len(posts) - 1:
+                    time.sleep(0.5)
+
         return ThreadResult(
             success=True,
             thread_uri=root_uri,