Remove newFilesOnly toggle; add functional notifications; fix WiFi status

WHAT TO BACK UP section:
- Remove "New files only" / "Skip files already on NAS" toggle from Settings
- Remove BackupFilter.newFilesOnly field — duplicate protection is always active
  (fileExists pre-check + hybrid filterIndex ensure NAS files are never re-uploaded)

NOTIFICATIONS section:
- Replace static decorative rows with real ToggleRow controls backed by
  ConnectionStore (notifyOnStart=false, notifyOnComplete=true, notifyOnErrors=true)
- BackupEngine now gates notification calls behind these store flags

NETWORK section:
- WiFi row always shows ● On / ● Off indicator (was only shown when SSID known)
- Shows "Trusted" / "Unknown" when SSID is available, "On" / "Off" otherwise

Tests:
- makeAssets: add missing isScreenRecording parameter
- Rename test_backup_skipsExistingFiles_whenNewFilesOnly → _alwaysHardcoded,
  remove filter.newFilesOnly assignment
- MockNASService: add downloadData, writeData, deleteFile to satisfy protocol

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

Core/Protocols/PhotoLibraryProtocol.swift

@@ -26,6 +26,5 @@ struct BackupFilter: Codable, Sendable, Equatable {
     var includeVideos: Bool = true
     var includeScreenshots: Bool = false
     var includeRAW: Bool = false
-    var newFilesOnly: Bool = true
     var includeScreenRecordings: Bool = false
 }