Complete Payment module: initiate/webhook/confirm/refund actions, Filament resources (T5.8-T5.13)

- InitiatePaymentAction + POST /api/v1/payments/{booking}/initiate
- Generic KBZ webhook (POST /api/v1/webhooks/{method}/{encryptBookingId?}),
  signature verification per KBZ's real callback spec, PaymentGatewayInterface::handleWebhook()
- ConfirmPaymentAction: idempotent confirmation, PaymentCompleted/PaymentFailed events,
  MarkBookingPaid listener
- RefundBookingAction + POST /api/v1/bookings/{booking}/refund: partial refunds validated
  against remaining balance, RefundProcessed event, MarkBookingRefunded listener
- CancelBookingAction now refunds confirmed bookings instead of rejecting; BookingPolicy::cancel
  requires process_refunds for confirmed bookings
- PaymentPlugin + PaymentResource/RefundResource Filament admin UI (read-only payments,
  refund list + Process action)
- Booking detail page now shows related payments
- Fix CACHE_STORE mismatch (database -> redis) so tagged route caching works
- CLAUDE.md: never run migrate:fresh/migrate:refresh/db:wipe on dev without being asked

app-modules/payment/src/Exceptions/PaymentInitiationNotAllowedException.php

@@ -0,0 +1,27 @@
+<?php
+
+namespace Modules\Payment\Exceptions;
+
+use Illuminate\Http\JsonResponse;
+use Illuminate\Http\Request;
+use Modules\Booking\Models\Booking;
+use RuntimeException;
+
+class PaymentInitiationNotAllowedException extends RuntimeException
+{
+    public static function notPendingPayment(Booking $booking): self
+    {
+        return new self(
+            "Booking [{$booking->booking_ref}] cannot have a payment initiated because its status is [{$booking->status->value}], not pending_payment."
+        );
+    }
+
+    public function render(Request $request): ?JsonResponse
+    {
+        if ($request->expectsJson()) {
+            return response()->json(['message' => $this->getMessage()], 422);
+        }
+
+        return null;
+    }
+}