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.API/Models/Public/PushDtos.cs

@@ -0,0 +1,17 @@
+namespace Meezi.API.Models.Public;
+
+/// <summary>Device registration from the native (Capacitor + Pushe) shell.</summary>
+public record RegisterPushDeviceRequest(
+    string Token,
+    string Platform = "android",
+    string? City = null,
+    string? ConsumerAccountId = null);
+
+public record UnregisterPushDeviceRequest(string Token);
+
+/// <summary>Broadcast a push to a Pushe topic (city-{slug} / cafe-{slug}).</summary>
+public record BroadcastPushRequest(
+    string Topic,
+    string Title,
+    string Body,
+    string? DeepLink = null);