Fix AP re-publish: use versioned object IDs after Delete

After Delete + re-Create, Mastodon tombstones the old object ID and
ignores new Creates with the same ID. Now appends /v2, /v3 etc. so
remote servers treat re-publishes as fresh posts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

services/stubs.py

@@ -217,6 +217,9 @@ class StubFederationService:
     async def get_activity_for_source(self, session, source_type, source_id):
         return None
 
+    async def count_activities_for_source(self, session, source_type, source_id, *, activity_type):
+        return 0
+
     async def get_followers(self, session, username):
         return []