Session Cache Implementation

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

NucleicRemote/NucleicRemote/Models/RemoteStore.swift

@@ -598,7 +598,18 @@ final class RemoteStore: ObservableObject {
     /// or a representative one. No-op in demo, which seeds the aggregate directly.
     private func rebuildAggregate() {
         guard !demoMode else { return }
-        sessions = aggregatedSessions()
+        let live = aggregatedSessions()
+        if !live.isEmpty {
+            sessions = live
+            cachedSummaries = live
+            persistSummaries(live)
+        } else if connections.values.contains(where: { $0.connectivity.isLive }) {
+            // Connected, but the host genuinely has no sessions — reflect that honestly.
+            sessions = []
+        } else {
+            // Offline: keep showing the saved history rather than blanking the list.
+            sessions = cachedSummaries
+        }
         dashboard = DashboardSnapshot.merged(connections.values.map(\.dashboard))
         meshPeers = connections.values.flatMap(\.meshPeers)