Log when migrating thread metadata in `ThreadMetadataStore` (#52230)

Bennet Bo Fenner created

## Context

This will make it easier to diagnose issues if any come up when
migrating thread metadata for the sidebar

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## Self-Review Checklist

<!-- Check before requesting review: -->
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Release Notes:

- N/A

Change summary

crates/agent_ui/src/thread_metadata_store.rs | 4 ++++
1 file changed, 4 insertions(+)

Detailed changes

crates/agent_ui/src/thread_metadata_store.rs 🔗

@@ -83,12 +83,16 @@ fn migrate_thread_metadata(cx: &mut App) {
                 .collect::<Vec<_>>()
         });
 
+        log::info!("Migrating {} thread store entries", metadata.len());
+
         // Manually save each entry to the database and call reload, otherwise
         // we'll end up triggering lots of reloads after each save
         for entry in metadata {
             db.save(entry).await?;
         }
 
+        log::info!("Finished migrating thread store entries");
+
         let _ = store.update(cx, |store, cx| store.reload(cx));
         Ok(())
     })