Add push notifications (Pushe) + Capacitor shell for Koja

Iran-safe push for the Koja Android app (Cafe Bazaar / Myket / direct APK):

Backend
- PushDevice entity + EF migration; idempotent device register/unregister.
- IPushSender / PusheNotificationSender (Pushe REST) — SendToTopic for
  marketing (city-{slug}) and saved-café (cafe-{slug}) pushes, SendToTokens
  for targeted order/reservation updates.
- Public register/unregister endpoints + authorized topic broadcast.

App
- capacitor.config.ts (native WebView loads the live PWA via server.url).
- push.ts Pushe glue: topic helpers + backend device registration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/Meezi.Core/Entities/PushDevice.cs

@@ -0,0 +1,24 @@
+namespace Meezi.Core.Entities;
+
+/// <summary>
+/// A registered push-notification device (Pushe). One row per install token.
+/// Used for targeted order/reservation pushes; broadcast/marketing pushes go
+/// through Pushe topics (city-{slug}, cafe-{slug}) the device subscribes to
+/// client-side, but we mirror the city here for server-side fallback targeting.
+/// </summary>
+public class PushDevice : BaseEntity
+{
+    /// <summary>Pushe device/install token.</summary>
+    public string Token { get; set; } = string.Empty;
+
+    /// <summary>"android" (only platform shipped today).</summary>
+    public string Platform { get; set; } = "android";
+
+    /// <summary>Optional city slug the user is browsing — for city-topic targeting.</summary>
+    public string? City { get; set; }
+
+    /// <summary>Optional link to a platform consumer account (OTP login).</summary>
+    public string? ConsumerAccountId { get; set; }
+
+    public DateTime LastSeenAt { get; set; } = DateTime.UtcNow;
+}