Add Swift app for iPod contacts and calendar export

Replaces the bash/AppleScript/Python app bundle with a SwiftUI app backed
by a testable library target.

The app now reads Contacts and EventKit directly rather than sanitizing
files someone exported by hand, so the properties that break click-wheel
firmware are never written instead of being stripped afterwards: no PHOTO,
no X-, no VALARM, no VTIMEZONE, no TZID. Recurring events arrive from
EventKit already expanded into occurrences, so no RRULE is emitted either
- the open question from the previous version no longer applies.

Sanitizing existing .vcf/.ics files is kept as a second path, and gains
handling the Python lacked: vCard 2.1 quoted-printable soft line breaks,
Apple's item1. property groups, nested STANDARD/DAYLIGHT components inside
VTIMEZONE, and UTC times converted to local floating times.

Output is laid out as Contacts/ and Calendars/ subfolders mirroring the
device, one file per contact and one per calendar.

Built via SwiftPM plus Scripts/bundle.sh, which assembles and ad-hoc signs
the bundle. Ad-hoc signing is required rather than cosmetic: Contacts and
Calendars key permissions off the code signature.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01C5X1tYo9oxAfvoiFMh1QQr

Package.swift

@@ -0,0 +1,18 @@
+// swift-tools-version: 6.2
+import PackageDescription
+
+let package = Package(
+    name: "iPodContactsAndCalendarSync",
+    platforms: [.macOS(.v14)],
+    targets: [
+        .target(name: "IPodSyncKit"),
+        .executableTarget(
+            name: "iPodSyncApp",
+            dependencies: ["IPodSyncKit"]
+        ),
+        .testTarget(
+            name: "IPodSyncKitTests",
+            dependencies: ["IPodSyncKit"]
+        ),
+    ]
+)