Session Cache Implementation

Nucleic-Session: B2346642-3353-4BD5-9DE2-A8B77BD66C98
Co-authored-by: Nucleic <[email protected]>

NucleicRemote/NucleicRemote/Models/RemoteStore.swift

@@ -521,16 +521,19 @@ final class RemoteStore: ObservableObject {
             // instead of truncating it to the host's 200-event tail.
             self.openEvents = Self.mergedEvents(self.openEvents, snap.recentEvents)
             self.openApprovals = snap.pendingApprovals
+            self.persistOpenTranscript()
         }
         cb.openEvents = { [weak self] batch in
             guard let self, hostID == self.openSessionHostID, batch.sessionID == self.openSessionID else { return }
             self.openEvents.append(contentsOf: batch.events)
+            self.persistOpenTranscript()
         }
         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)
+            self.persistOpenTranscript()
         }
         cb.openDiff = { [weak self] diff in
             guard let self, hostID == self.openSessionHostID, diff.sessionID == self.openSessionID else { return }