完璧に動作しています。

テスト	結果
確定取消 API	✅ is_confirmed: false, confirmed_at: null
USE トランザクション削除	✅ current_stock が 27.5→32 に復帰
引当再作成	✅ reserved_stock = 5.000 に復帰
追加した変更:

stock_service.py:81-93 — unconfirm_spreading(): USE削除→確定フラグリセット→引当再作成
fertilizer/views.py — unconfirm アクション（POST /api/fertilizer/plans/{id}/unconfirm/）
fertilizer/page.tsx — 一覧に「確定取消」ボタン（確定済み計画のみ表示）
FertilizerEditPage.tsx — 編集画面ヘッダーに「確定取消」ボタン + 在庫情報再取得

backend/apps/materials/views.py

@@ -103,32 +103,62 @@ class StockSummaryView(generics.ListAPIView):
 
         results = []
         for material in queryset:
-            transactions = list(material.stock_transactions.all())
-            increase = sum(
-                txn.quantity
-                for txn in transactions
-                if txn.transaction_type in StockTransaction.INCREASE_TYPES
-            )
-            decrease = sum(
-                txn.quantity
-                for txn in transactions
-                if txn.transaction_type in StockTransaction.DECREASE_TYPES
-            )
-            last_date = max((txn.occurred_on for txn in transactions), default=None)
-            results.append(
-                {
-                    'material_id': material.id,
-                    'name': material.name,
-                    'material_type': material.material_type,
-                    'material_type_display': material.get_material_type_display(),
-                    'maker': material.maker,
-                    'stock_unit': material.stock_unit,
-                    'stock_unit_display': material.get_stock_unit_display(),
-                    'is_active': material.is_active,
-                    'current_stock': increase - decrease if transactions else Decimal('0'),
-                    'last_transaction_date': last_date,
-                }
-            )
+            results.append(_build_stock_summary(material))
 
         serializer = self.get_serializer(results, many=True)
         return Response(serializer.data)
+
+
+class FertilizerStockView(generics.ListAPIView):
+    """施肥計画画面用: 肥料の在庫情報を返す"""
+
+    permission_classes = [IsAuthenticated]
+    serializer_class = StockSummarySerializer
+
+    def get_queryset(self):
+        return Material.objects.none()
+
+    def list(self, request, *args, **kwargs):
+        queryset = Material.objects.filter(
+            material_type=Material.MaterialType.FERTILIZER,
+            is_active=True,
+        ).prefetch_related('stock_transactions').order_by('name')
+
+        results = [_build_stock_summary(material) for material in queryset]
+        serializer = self.get_serializer(results, many=True)
+        return Response(serializer.data)
+
+
+def _build_stock_summary(material):
+    transactions = list(material.stock_transactions.all())
+    increase = sum(
+        txn.quantity
+        for txn in transactions
+        if txn.transaction_type in StockTransaction.INCREASE_TYPES
+    )
+    decrease = sum(
+        txn.quantity
+        for txn in transactions
+        if txn.transaction_type in StockTransaction.DECREASE_TYPES
+    )
+    reserved = sum(
+        txn.quantity
+        for txn in transactions
+        if txn.transaction_type == StockTransaction.TransactionType.RESERVE
+    )
+    available = increase - decrease if transactions else Decimal('0')
+    last_date = max((txn.occurred_on for txn in transactions), default=None)
+    return {
+        'material_id': material.id,
+        'name': material.name,
+        'material_type': material.material_type,
+        'material_type_display': material.get_material_type_display(),
+        'maker': material.maker,
+        'stock_unit': material.stock_unit,
+        'stock_unit_display': material.get_stock_unit_display(),
+        'is_active': material.is_active,
+        'current_stock': available + reserved,
+        'reserved_stock': reserved,
+        'available_stock': available,
+        'last_transaction_date': last_date,
+    }