分配計画を運搬計画に再設計: 軽トラ1回分を基本単位とする運搬回モデルを導入

実運用のワークフロー（複数施肥計画混在・軽トラ複数回・肥料指定）に合わせ、
旧 DistributionPlan/Group/GroupField を DeliveryPlan/Group/GroupField/Trip/TripItem に置き換え。
施肥計画への直接FK廃止→年度ベースで全施肥計画を横断。
回ごとの日付記録、圃場の回間移動、対象肥料フィルタ、回ごとPDF出力に対応。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/apps/fertilizer/migrations/0007_delivery_models.py

@@ -0,0 +1,127 @@
+# Generated by Django 5.0 on 2026-03-16 07:11
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('fertilizer', '0006_fertilizationplan_confirmation'),
+        ('fields', '0006_e1c_chusankan_17_fields'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='DeliveryGroup',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, verbose_name='グループ名')),
+                ('order', models.PositiveIntegerField(default=0, verbose_name='表示順')),
+            ],
+            options={
+                'verbose_name': '配送先グループ',
+                'verbose_name_plural': '配送先グループ',
+                'ordering': ['order', 'id'],
+            },
+        ),
+        migrations.CreateModel(
+            name='DeliveryPlan',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('year', models.IntegerField(verbose_name='年度')),
+                ('name', models.CharField(max_length=200, verbose_name='計画名')),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+            ],
+            options={
+                'verbose_name': '運搬計画',
+                'verbose_name_plural': '運搬計画',
+                'ordering': ['-year', 'name'],
+            },
+        ),
+        migrations.RemoveField(
+            model_name='distributiongroupfield',
+            name='group',
+        ),
+        migrations.AlterUniqueTogether(
+            name='distributiongroupfield',
+            unique_together=None,
+        ),
+        migrations.RemoveField(
+            model_name='distributiongroupfield',
+            name='distribution_plan',
+        ),
+        migrations.RemoveField(
+            model_name='distributiongroupfield',
+            name='field',
+        ),
+        migrations.RemoveField(
+            model_name='distributionplan',
+            name='fertilization_plan',
+        ),
+        migrations.CreateModel(
+            name='DeliveryGroupField',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('field', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to='fields.field', verbose_name='圃場')),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='field_assignments', to='fertilizer.deliverygroup', verbose_name='グループ')),
+                ('delivery_plan', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to='fertilizer.deliveryplan', verbose_name='運搬計画')),
+            ],
+            options={
+                'verbose_name': 'グループ圃場割り当て',
+                'verbose_name_plural': 'グループ圃場割り当て',
+                'ordering': ['field__display_order', 'field__id'],
+                'unique_together': {('delivery_plan', 'field')},
+            },
+        ),
+        migrations.AddField(
+            model_name='deliverygroup',
+            name='delivery_plan',
+            field=models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='groups', to='fertilizer.deliveryplan', verbose_name='運搬計画'),
+        ),
+        migrations.CreateModel(
+            name='DeliveryTrip',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('order', models.PositiveIntegerField(default=0, verbose_name='何回目')),
+                ('name', models.CharField(blank=True, max_length=100, verbose_name='名前')),
+                ('date', models.DateField(blank=True, null=True, verbose_name='運搬日')),
+                ('delivery_plan', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='trips', to='fertilizer.deliveryplan', verbose_name='運搬計画')),
+            ],
+            options={
+                'verbose_name': '運搬回',
+                'verbose_name_plural': '運搬回',
+                'ordering': ['order', 'id'],
+            },
+        ),
+        migrations.CreateModel(
+            name='DeliveryTripItem',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('bags', models.DecimalField(decimal_places=4, max_digits=10, verbose_name='袋数')),
+                ('fertilizer', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to='fertilizer.fertilizer', verbose_name='肥料')),
+                ('field', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, to='fields.field', verbose_name='圃場')),
+                ('trip', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='items', to='fertilizer.deliverytrip', verbose_name='運搬回')),
+            ],
+            options={
+                'verbose_name': '運搬明細',
+                'verbose_name_plural': '運搬明細',
+                'ordering': ['field__display_order', 'field__id', 'fertilizer__name'],
+                'unique_together': {('trip', 'field', 'fertilizer')},
+            },
+        ),
+        migrations.DeleteModel(
+            name='DistributionGroup',
+        ),
+        migrations.DeleteModel(
+            name='DistributionGroupField',
+        ),
+        migrations.DeleteModel(
+            name='DistributionPlan',
+        ),
+        migrations.AlterUniqueTogether(
+            name='deliverygroup',
+            unique_together={('delivery_plan', 'name')},
+        ),
+    ]