feat: payments module, notification templates, WA float, route fixes

- Add PaymentsModule: POST /payments/intent, POST /:id/confirm, GET /payments, GET /payments/package/:id, GET /payments/track/:trackingId
- Add Payment model to Prisma schema (PaymentStatus enum, Payment table)
- Add NotificationTemplate model + NotificationsController (GET/PUT /notification-templates, POST /notification-templates/seed)
- Update NotificationsService: DB-backed templates with variable interpolation {{trackingId}} {{firstName}} {{status}} {{suiteCode}}
- Fix /bodega/paquetes: replace 11 wrong status strings with correct §08 enum values
- Fix /admin/reportes: replace EN_CAMINO_A_ECUADOR with correct §08 statuses, rewrite report page with proper KPIs and bar charts
- Fix /portal/mis-paquetes: correct §08 statuses, add 'Pagar envío' button for VERIFICADO/DECLARACION_ADUANERA packages
- Add WhatsApp float component (_components/whatsapp-float.tsx, 2 contacts: NJ ops + Cuenca aduana)
- Add /casillero/calculadora and /casillero/registro redirects (§20)
- Add /portal/pago payment page with cost breakdown (§09/§14/§15)
- Add /admin/notificaciones page: view/edit/toggle templates per event×channel
- Admin nav: add Notificaciones link
- api.ts: add notificationTemplates.* and payments.* client methods
- schema.prisma v0.4: PaymentStatus enum, Payment model, NotificationTemplate model
- db push applied to remote DB (46.202.93.92)
- All builds pass (API nest build + Next.js build)

apps/web/src/lib/api.ts

@@ -154,4 +154,19 @@ export const api = {
     batchUpsert: (items: Array<{ key: string; value: string | null; isActive: boolean }>) =>
       request<any>("/integrations/batch", { method: "PUT", body: JSON.stringify({ items }) }),
   },
+  notificationTemplates: {
+    list:  () => request<any[]>("/notification-templates"),
+    seed:  () => request<any>("/notification-templates/seed", { method: "POST" }),
+    update: (id: string, body: { body: string; subject?: string; isActive?: boolean }) =>
+      request<any>(`/notification-templates/${id}`, { method: "PUT", body: JSON.stringify(body) }),
+  },
+  payments: {
+    list:          (status?: string) => request<any[]>(`/payments${status ? `?status=${status}` : ""}`),
+    packageDetail: (packageId: string) => request<any>(`/payments/package/${packageId}`),
+    byTracking:    (trackingId: string) => request<any>(`/payments/track/${trackingId}`),
+    createIntent:  (packageId: string, provider = "stripe") =>
+      request<any>("/payments/intent", { method: "POST", body: JSON.stringify({ packageId, provider }) }),
+    confirm:       (paymentId: string) =>
+      request<any>(`/payments/${paymentId}/confirm`, { method: "POST" }),
+  },
 };