Add IndieAbout + IndieBackup, TestFlight release pipeline

IndieAbout: About section in iOS Settings and macOS About window; LICENSE
switched to the portfolio-standard ISC text (reflowed for in-app rendering).

IndieBackup: files-only backup/restore of the iCloud container documents
('.notesbackup' document type on both platforms), SwiftData cache rebuilt
via SyncEngine.rebuildCache() after restore, monitors suspended during the
file swap, onOpenURL import with pre-launch queueing.

Release pipeline: Scripts/release.sh (ios|mac|all) archives and uploads via
xcodebuild + ASC API key; platform-partitioned build numbers (iOS even,
macOS odd) since both targets share one bundle ID and build sequence.

Notes/AppServices/AppServices.swift

@@ -1,4 +1,5 @@
 import Foundation
+import IndieBackup
 import SwiftData
 
 /// Owns all service objects; created asynchronously at launch and injected
@@ -9,14 +10,23 @@ final class AppServices {
     let modelContainer: ModelContainer
     let syncEngine: SyncEngine
     let contextService: ContextService
+    let backupController: BackupController
 
     init() async {
         let container = NotesModelContainer.make()
         self.modelContainer = container
-        self.syncEngine = SyncEngine(modelContainer: container)
+        let engine = SyncEngine(modelContainer: container)
+        self.syncEngine = engine
         self.contextService = ContextService()
+        self.backupController = BackupController(
+            configuration: NotesBackupConfiguration(syncEngine: engine)
+        )
     }
 
+    /// The file extension this app owns for backup documents. Used to route
+    /// `onOpenURL` imports to a restore.
+    var backupFileExtension: String { backupController.configuration.backupFileExtension }
+
     /// Slow startup work (iCloud container discovery) — runs after the UI is up.
     func startDeferredServices() async {
         await syncEngine.connect()