Add the watchOS app and complication targets

The companion dropdown in Xcode's target template came up empty, which left
both bundle identifiers starting with a bare dot and
WKCompanionAppBundleIdentifier as an empty string. Both are set explicitly
here, along with the App Group entitlements and watchOS 26 as the floor.

The iOS app had no Embed Watch Content phase, so the watch app would have built
and never shipped. Added, with the matching target dependency: the product now
lands at Calendarr iOS.app/Watch/CalendarrWatch.app with the complications
inside it.

Folders follow what they contain: CalendarrWatch is the app,
CalendarrWatchComplications the extension. Xcode had them the other way round.

Package.resolved is now tracked. It pins AppAuth, whose version drift is what
produced the two compile errors fixed in 75a6a5b.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CalendarrWatch/CalendarrWatchApp.swift

@@ -0,0 +1,17 @@
+//
+//  CalendarrWatchApp.swift
+//  CalendarrWatch Watch App
+//
+//  Created by Guido Schmit on 11.09.2026.
+//
+
+import SwiftUI
+
+@main
+struct CalendarrWatch_Watch_AppApp: App {
+    var body: some Scene {
+        WindowGroup {
+            ContentView()
+        }
+    }
+}