Phase 4.A.1: Live Activity + Dynamic Island für laufende Gassi-Tour

Neues Widget-Extension-Target BanYaroGoWidgetExtension:
- Bundle-ID app.banyaro.ios.BanYaroGoWidget
- NSExtensionPointIdentifier = com.apple.widgetkit-extension
- Synced root group + explizite Info.plist + Embed-Phase in App-Target
- Cross-Membership der Shared/WalkActivityAttributes.swift in beiden Targets

Shared/WalkActivityAttributes.swift:
- ActivityAttributes mit startedAt (fix)
- ContentState mit distanceMeters, elapsedSeconds, pointCount, isPaused, isAutoPaused

BanYaroGoWidget/WalkLiveActivity.swift:
- Lock-Screen-View: Pfote-Icon + Status-Pille (Live/Pause/Auto-Pause) +
  Stats-Spalten (Distanz/Dauer/Punkte)
- Dynamic Island compact: Pfote leading, Distanz trailing
- Dynamic Island minimal: nur Pfote
- Dynamic Island expanded: Distanz/Dauer/Status mit Pfote zentriert

WalkActivityController:
- @MainActor Facade um ActivityKit
- start() prüft areActivitiesEnabled, killt orphaned current, request mit Initial-State
- update() async via Task
- end() mit dismissalPolicy.immediate

TrackingView:
- .onChange(of: tracker.isTracking) → Start/End
- persistTicker (5s) → update
- .onChange(of: tracker.isPaused/isAutoPaused) → sofort update für saubere UX

BanYaroGo-Info.plist: NSSupportsLiveActivities = true

BanYaroGo-Info.plist

@@ -58,5 +58,7 @@
 	<array>
 		<string>location</string>
 	</array>
+	<key>NSSupportsLiveActivities</key>
+	<true/>
 </dict>
 </plist>