Fetch Historical Transcript Data

Nucleic-Session: 11465D90-A8F3-43AA-A1DC-37EA1EC1B909
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/Models/RemoteStore.swift

@@ -487,6 +487,12 @@ final class RemoteStore: ObservableObject {
             guard let self, hostID == self.openSessionHostID, batch.sessionID == self.openSessionID else { return }
             self.openEvents.append(contentsOf: batch.events)
         }
+        cb.openBackfill = { [weak self] batch in
+            guard let self, hostID == self.openSessionHostID, batch.sessionID == self.openSessionID else { return }
+            // Full-history backfill precedes what's on screen — merge by seq so it slots in above the
+            // tail rather than appending out of order.
+            self.openEvents = Self.mergedEvents(self.openEvents, batch.events)
+        }
         cb.openDiff = { [weak self] diff in
             guard let self, hostID == self.openSessionHostID, diff.sessionID == self.openSessionID else { return }
             self.openDiff = diff