feat(core): consolidate auth service into backend and implement stripe billing

This commit performs a major architectural refactor by migrating the standalone `auth-service` into the main `backend` application, enabling a unified codebase and simplified deployment. It also introduces comprehensive Stripe billing support and a new administrative dashboard.

Key changes:
- **Architecture**: Deleted `apps/auth-service` and integrated its functionality (JWT, magic links, OAuth, user management) into `apps/backend`.
- **Billing**: Added Stripe integration to `backend`, supporting both monthly and yearly subscription cycles with automatic plan entitlement enforcement (e.g., location limits).
- **Admin Dashboard**: Implemented a new administrative service and API endpoints to manage tenants, users, and view platform-wide statistics.
- **Frontend**:
    - Added a new pricing page with monthly/yearly toggle and comparison table.
    - Integrated Stripe and Sentry for payments and error tracking.
    - Improved dashboard UX/UI and added i18n support for new features.
    - Enhanced the public booking flow with better validation and contact form integration.
- **Database**: Added migrations for users, magic links, password resets, OAuth states, admin audit logs, and refresh tokens.
- **DevOps**: Updated environment configurations for Railway and Vercel, and streamlined the project's `package.json` scripts.

apps/frontend/src/lib/sentry.ts

@@ -0,0 +1,27 @@
+import * as Sentry from "@sentry/react";
+
+export function initSentry() {
+  const dsn = import.meta.env.VITE_SENTRY_DSN;
+  
+  if (!dsn) {
+    console.log("Sentry DSN not configured - skipping initialization");
+    return;
+  }
+
+  Sentry.init({
+    dsn,
+    integrations: [
+      Sentry.browserTracingIntegration(),
+      Sentry.replayIntegration({
+        maskAllText: false,
+        blockAllMedia: false,
+      }),
+    ],
+    tracesSampleRate: 1.0,
+    replaysSessionSampleRate: 0.1,
+    replaysOnErrorSampleRate: 1.0,
+    enableLogs: true,
+    environment: import.meta.env.MODE,
+    release: `bookra@${import.meta.env.VITE_APP_VERSION || "1.0.0"}`,
+  });
+}