Add refund action to booking list/detail with full-refund toggle

- New RefundBookingTableAction on the booking list row and detail page,
  refunding a Confirmed booking directly via RefundBookingAction — no need
  to hunt up its Payment on the Refunds resource first.
- Payment::refundableBalance() extracted from RefundBookingAction's private
  balance check so both refund forms can display and cap against it.
- RefundBookingAction::resolveRefundablePayment() made public for the same
  reason (round-trip leg resolution reused by the UI).
- Both refund forms (ProcessRefundAction and the new booking action) gain a
  "Full refund" toggle, on by default, which refunds the payment's whole
  remaining balance without requiring a manually typed amount. Turning it
  off reveals an amount field capped at the refundable balance.

app-modules/payment/tests/Feature/RefundResourceTest.php

@@ -77,7 +77,7 @@ test('the process action is visible to a user with process_refunds', function ()
         ->assertActionVisible('process');
 });
 
-test('processing a refund via the action calls RefundBookingAction and cancels the booking', function () {
+test('processing a partial refund via the action calls RefundBookingAction and cancels the booking', function () {
     $admin = User::factory()->create()->givePermissionTo(['view_payments', 'process_refunds']);
     $this->actingAs($admin);
 
@@ -92,13 +92,64 @@ test('processing a refund via the action calls RefundBookingAction and cancels t
     Livewire::test(ListRefunds::class)
         ->callAction('process', data: [
             'payment_id' => $payment->id,
-            'amount' => 15000,
+            'full_refund' => false,
+            'amount' => 5000,
             'reason' => 'customer requested cancellation',
         ])
         ->assertNotified();
 
     expect($booking->refresh()->status)->toBe(BookingStatus::Cancelled)
-        ->and(Refund::where('payment_id', $payment->id)->where('status', RefundStatus::Completed)->exists())->toBeTrue();
+        ->and(Refund::where('payment_id', $payment->id)->where('status', RefundStatus::Completed)->where('amount', 5000)->exists())->toBeTrue();
+});
+
+test('the full refund toggle refunds the payment\'s whole refundable balance without an amount input', function () {
+    $admin = User::factory()->create()->givePermissionTo(['view_payments', 'process_refunds']);
+    $this->actingAs($admin);
+
+    $booking = Booking::factory()->create(['status' => BookingStatus::Confirmed, 'price' => 15000]);
+    $payment = Payment::factory()->completed()->create([
+        'booking_id' => $booking->id,
+        'gateway' => PaymentMethod::KbzMiniApp,
+        'amount' => 15000,
+        'gateway_transaction_id' => 'EVB-FILAMENT-FULL-1',
+    ]);
+
+    Livewire::test(ListRefunds::class)
+        ->callAction('process', data: [
+            'payment_id' => $payment->id,
+            'full_refund' => true,
+            'reason' => 'customer requested cancellation',
+        ])
+        ->assertNotified();
+
+    expect(Refund::where('payment_id', $payment->id)->where('status', RefundStatus::Completed)->where('amount', 15000)->exists())->toBeTrue();
+});
+
+test('the full refund toggle defaults to on', function () {
+    $admin = User::factory()->create()->givePermissionTo(['view_payments', 'process_refunds']);
+    $this->actingAs($admin);
+
+    Livewire::test(ListRefunds::class)
+        ->mountAction('process')
+        ->assertActionDataSet(['full_refund' => true]);
+});
+
+test('turning the full refund toggle off requires an amount', function () {
+    $admin = User::factory()->create()->givePermissionTo(['view_payments', 'process_refunds']);
+    $this->actingAs($admin);
+
+    $payment = Payment::factory()->completed()->create([
+        'gateway' => PaymentMethod::KbzMiniApp,
+        'amount' => 15000,
+    ]);
+
+    Livewire::test(ListRefunds::class)
+        ->callAction('process', data: [
+            'payment_id' => $payment->id,
+            'full_refund' => false,
+            'reason' => 'reason',
+        ])
+        ->assertHasFormErrors(['amount' => 'required']);
 });
 
 test('a non-completed payment is not offered in the process action\'s payment select', function () {
@@ -151,3 +202,27 @@ test('a payment whose booking has been soft-deleted is not offered in the proces
 
     expect(Refund::where('payment_id', $payment->id)->exists())->toBeFalse();
 });
+
+test('the process action\'s amount field is capped at the selected payment\'s refundable balance', function () {
+    $admin = User::factory()->create()->givePermissionTo(['view_payments', 'process_refunds']);
+    $this->actingAs($admin);
+
+    $booking = Booking::factory()->create(['status' => BookingStatus::Confirmed, 'price' => 15000]);
+    $payment = Payment::factory()->completed()->create([
+        'booking_id' => $booking->id,
+        'gateway' => PaymentMethod::KbzMiniApp,
+        'amount' => 15000,
+        'gateway_transaction_id' => 'EVB-FILAMENT-MAX-1',
+    ]);
+
+    Livewire::test(ListRefunds::class)
+        ->callAction('process', data: [
+            'payment_id' => $payment->id,
+            'full_refund' => false,
+            'amount' => 15000.01,
+            'reason' => 'reason',
+        ])
+        ->assertHasFormErrors(['amount' => 'max']);
+
+    expect(Refund::where('payment_id', $payment->id)->exists())->toBeFalse();
+});

app-modules/payment/tests/Unit/PaymentRefundableBalanceTest.php

@@ -0,0 +1,28 @@
+<?php
+
+use Modules\Payment\Models\Payment;
+use Modules\Payment\Models\Refund;
+
+test('refundable balance is the full amount when nothing has been refunded yet', function () {
+    $payment = Payment::factory()->completed()->create(['amount' => 15000]);
+
+    expect($payment->refundableBalance())->toBe('15000.00');
+});
+
+test('refundable balance subtracts only completed refunds', function () {
+    $payment = Payment::factory()->completed()->create(['amount' => 15000]);
+
+    Refund::factory()->completed()->for($payment)->create(['amount' => 5000]);
+    Refund::factory()->failed()->for($payment)->create(['amount' => 3000]);
+    Refund::factory()->for($payment)->create(['amount' => 2000]); // default state is Pending
+
+    expect($payment->refundableBalance())->toBe('10000.00');
+});
+
+test('refundable balance reaches zero once fully refunded', function () {
+    $payment = Payment::factory()->completed()->create(['amount' => 15000]);
+
+    Refund::factory()->completed()->for($payment)->create(['amount' => 15000]);
+
+    expect($payment->refundableBalance())->toBe('0.00');
+});