fix: always refresh NAS dir count, show connection status, fix screenshot filter reactivity

- buildManifestIndex now always scans the NAS directory on every full reconcile
  (removed the `totalCount <= 1` guard) so NAS Archive count updates accurately
  on every manual refresh, not just when the manifest is new/sparse
- The dir > manifest check still switches to filename-based matching when the
  directory has more files than Kisani's manifest (uploaded by other tools)
- checkStatusRow shows NAS connection status (orange dot + "NAS Connected" /
  red dot + "NAS Offline") below the timestamp line
- BackupFilter now conforms to Equatable; BackupView re-reconciles immediately
  when the screenshot/video/RAW filter toggles change

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

Core/Protocols/PhotoLibraryProtocol.swift

@@ -20,7 +20,7 @@ protocol PhotoLibraryProtocol: AnyObject {
     func exportAsset(_ asset: PhotoAsset) async throws -> URL
 }
 
-struct BackupFilter: Codable, Sendable {
+struct BackupFilter: Codable, Sendable, Equatable {
     var includePhotos: Bool = true
     var includeVideos: Bool = true
     var includeScreenshots: Bool = false