fix: startup migration syncs stale CRDT stages from pipeline_items DB

510 stories had stale 1_backlog stages in the CRDT because they were
imported during the filesystem→CRDT migration and then moved forward
via filesystem-only moves that never wrote CRDT ops. This made done
stories appear as ghost entries in the backlog.

On startup, reads the authoritative stage from pipeline_items and
corrects any CRDT entries that disagree.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

server/src/main.rs

@@ -337,6 +337,12 @@ async fn main() -> Result<(), std::io::Error> {
         }
     }
 
+    // One-time fix: sync CRDT stages from pipeline_items DB for stories
+    // that were migrated with stale backlog stages.
+    if let Some(ref db_path) = pipeline_db_path {
+        db::sync_crdt_stages_from_db(db_path).await;
+    }
+
     // (CRDT state layer is initialised above alongside the legacy pipeline.db.)
 
     // Start the CRDT sync rendezvous client if configured in project.toml.