ARCH: add centralized MotorSignal entitlement capability model

lib/services/entitlements/entitlement_state.dart

@@ -0,0 +1,66 @@
+import 'package:flutter/foundation.dart';
+
+enum MotorSignalPlan {
+  free,
+  proMonthly,
+  proLifetime,
+}
+
+enum MotorSignalEntitlementStatus {
+  free,
+  proMonthlyActive,
+  proMonthlyGrace,
+  proMonthlyAccountHold,
+  proMonthlyExpired,
+  proLifetime,
+  unknown,
+  syncPending,
+}
+
+/// Central capability model. UI and services should depend on capabilities,
+/// not Google Play product IDs or scattered `isPro` checks.
+@immutable
+class EntitlementState {
+  final MotorSignalPlan plan;
+  final MotorSignalEntitlementStatus status;
+  final DateTime? expiresAt;
+
+  const EntitlementState({
+    this.plan = MotorSignalPlan.free,
+    this.status = MotorSignalEntitlementStatus.free,
+    this.expiresAt,
+  });
+
+  bool get isPro => plan != MotorSignalPlan.free &&
+      status != MotorSignalEntitlementStatus.proMonthlyExpired;
+
+  bool get canCloudBackup => true;
+  bool get canUnlimitedCloudHistory => isPro;
+  bool get canMultiDeviceRestore => isPro;
+  bool get canAdvancedTelemetry => isPro;
+  bool get canAdvancedAcceleration => isPro;
+  bool get canAdvancedBraking => isPro;
+  bool get canAdvancedLean => isPro;
+  bool get canAdvancedAnalytics => isPro;
+  bool get canUnlimitedHistory => isPro;
+  bool get canExportCsv => isPro;
+  bool get canExportPdf => isPro;
+  bool get canUseMultipleMotorcycles => isPro;
+  bool get canPlanTrips => isPro;
+  bool get canCreateGroupRides => isPro;
+  bool get canUseAdvancedGroupRideFeatures => isPro;
+
+  /// The Free cloud allowance is intentionally not hard-coded here. Product
+  /// economics will define the exact quota before launch.
+  int? get cloudRideAllowance => isPro ? null : null;
+
+  EntitlementState copyWith({
+    MotorSignalPlan? plan,
+    MotorSignalEntitlementStatus? status,
+    DateTime? expiresAt,
+  }) => EntitlementState(
+        plan: plan ?? this.plan,
+        status: status ?? this.status,
+        expiresAt: expiresAt ?? this.expiresAt,
+      );
+}