fix: NAS gallery shows backed-up files even when caches are cold

GalleryViewModel.load() now has a three-tier resolution for manifest entries:
  1. statusService.lastManifest — in-memory, freshest
  2. NASManifestCache disk cache — survives restarts
  3. Direct NAS download — fallback when both caches are cold (first launch after install,
     or before BackupStatusService reconcile has completed)

The direct download also populates NASManifestCache so subsequent opens are instant.

Also adds GalleryViewModel.bind(to:connection:) which subscribes to
statusService.$lastManifest and automatically reloads gallery items when
BackupStatusService finishes reconciling — gallery updates without manual pull-to-refresh.

Co-Authored-By: Kutesir <kutesir@provoc.ug>
Co-Authored-By: Sentry <sentry@provoc.ug>

Features/Browse/GalleryViewModel.swift

@@ -19,6 +19,8 @@ final class GalleryViewModel: ObservableObject {
     private(set) var allItems: [GalleryItem] = []
     private var loadTask: Task<Void, Never>?
     private var cancellables = Set<AnyCancellable>()
+    private weak var boundStatusService: BackupStatusService?
+    private var boundConnection: NASConnection?
 
     init() {
         $tab
@@ -33,18 +35,49 @@ final class GalleryViewModel: ObservableObject {
             .store(in: &cancellables)
     }
 
+    /// Call once to wire up reactive reloading when the manifest arrives.
+    func bind(to statusService: BackupStatusService, connection: NASConnection?) {
+        boundStatusService = statusService
+        boundConnection = connection
+        // When BackupStatusService finishes reconciling, reload if our items are stale.
+        statusService.$lastManifest
+            .dropFirst()
+            .compactMap { $0 }
+            .filter { !$0.entries.isEmpty }
+            .receive(on: RunLoop.main)
+            .sink { [weak self] manifest in
+                guard let self else { return }
+                // Only reload if the manifest has MORE items than what we're showing.
+                let currentNASCount = self.allItems.filter {
+                    if case .nas = $0.source { return true }
+                    if case .synced = $0.source { return true }
+                    return false
+                }.count
+                if manifest.entries.count > currentNASCount {
+                    Task { await self.load(connection: connection, statusService: statusService) }
+                }
+            }
+            .store(in: &cancellables)
+    }
+
     func load(connection: NASConnection?, statusService: BackupStatusService) async {
         loadTask?.cancel()
         isLoading = true
         nasError = nil
 
-        // Prefer the in-memory lastManifest (most recent reconcile), fall back to
-        // disk-cached NASManifestCache (survives launches without NAS connection).
-        let manifestEntries: [ManifestEntry]
-        if let m = statusService.lastManifest {
+        // Resolution order for manifest entries:
+        //  1. statusService.lastManifest — in-memory, freshest (set after each reconcile)
+        //  2. NASManifestCache disk cache — survives restarts without NAS connection
+        //  3. Direct NAS download — used when both caches are cold (first launch after install)
+        var manifestEntries: [ManifestEntry]
+        if let m = statusService.lastManifest, !m.entries.isEmpty {
             manifestEntries = m.entries
-        } else if let cached = await NASManifestCache.shared.manifest {
+        } else if let cached = await NASManifestCache.shared.manifest, !cached.entries.isEmpty {
             manifestEntries = cached.entries
+        } else if let conn = connection {
+            // Both caches are cold — download the manifest directly so the gallery
+            // isn't blank while BackupStatusService reconcile is still pending.
+            manifestEntries = await Self.fetchManifestDirect(conn: conn)
         } else {
             manifestEntries = []
         }
@@ -62,6 +95,25 @@ final class GalleryViewModel: ObservableObject {
         isLoading = false
     }
 
+    /// Downloads the NAS manifest directly when local caches are empty.
+    /// Caches the result so subsequent opens are instant.
+    private nonisolated static func fetchManifestDirect(conn: NASConnection) async -> [ManifestEntry] {
+        do {
+            let transfer: any NASTransferProtocol = conn.nasProtocol == .smb ? SMBService() : SFTPService()
+            try await transfer.connect(to: conn.host, port: conn.port,
+                                       username: conn.username, password: conn.password)
+            let path = "\(conn.remotePath)/\(BackupManifest.remoteFilename)"
+            let data = try await transfer.downloadData(at: path)
+            transfer.disconnect()
+            let manifest = try? JSONDecoder.kisani.decode(BackupManifest.self, from: data)
+            if let manifest {
+                await NASManifestCache.shared.update(manifest)
+                return manifest.entries
+            }
+        } catch {}
+        return []
+    }
+
     func recomputeSections() {
         let filtered = filteredItems()
         sections = buildSections(from: filtered)