在庫管理機能 Phase 1 実装（apps/materials + フロントエンド）

Backend:
- apps/materials 新規作成（Material, FertilizerProfile, PesticideProfile, StockTransaction）
- 資材マスタ CRUD API（/api/materials/materials/）
- 入出庫履歴 API（/api/materials/stock-transactions/）
- 在庫集計 API（/api/materials/stock-summary/）
- 既存 Fertilizer に material OneToOneField 追加（0005マイグレーション、データ移行込み）

Frontend:
- /materials: 在庫一覧画面（タブフィルタ、履歴展開、入出庫モーダル）
- /materials/masters: 資材マスタ管理（肥料/農薬/その他タブ、インライン編集）
- Navbar に「在庫管理」メニュー追加
- Material/StockTransaction/StockSummary 型定義追加

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

backend/apps/materials/migrations/0001_initial.py

@@ -0,0 +1,87 @@
+import decimal
+
+import django.core.validators
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = []
+
+    operations = [
+        migrations.CreateModel(
+            name='Material',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(max_length=100, verbose_name='資材名')),
+                ('material_type', models.CharField(choices=[('fertilizer', '肥料'), ('pesticide', '農薬'), ('seedling', '種苗'), ('other', 'その他')], max_length=20, verbose_name='資材種別')),
+                ('maker', models.CharField(blank=True, default='', max_length=100, verbose_name='メーカー')),
+                ('stock_unit', models.CharField(choices=[('bag', '袋'), ('bottle', '本'), ('kg', 'kg'), ('liter', 'L'), ('piece', '個')], default='bag', max_length=20, verbose_name='在庫単位')),
+                ('is_active', models.BooleanField(default=True, verbose_name='使用中')),
+                ('notes', models.TextField(blank=True, default='', verbose_name='備考')),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+            ],
+            options={
+                'verbose_name': '資材',
+                'verbose_name_plural': '資材',
+                'ordering': ['material_type', 'name'],
+            },
+        ),
+        migrations.CreateModel(
+            name='FertilizerProfile',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('capacity_kg', models.DecimalField(blank=True, decimal_places=3, max_digits=8, null=True, verbose_name='1袋重量(kg)')),
+                ('nitrogen_pct', models.DecimalField(blank=True, decimal_places=2, max_digits=5, null=True, verbose_name='窒素(%)')),
+                ('phosphorus_pct', models.DecimalField(blank=True, decimal_places=2, max_digits=5, null=True, verbose_name='リン酸(%)')),
+                ('potassium_pct', models.DecimalField(blank=True, decimal_places=2, max_digits=5, null=True, verbose_name='カリ(%)')),
+                ('material', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='fertilizer_profile', to='materials.material')),
+            ],
+            options={
+                'verbose_name': '肥料詳細',
+                'verbose_name_plural': '肥料詳細',
+            },
+        ),
+        migrations.CreateModel(
+            name='PesticideProfile',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('registration_no', models.CharField(blank=True, default='', max_length=100, verbose_name='農薬登録番号')),
+                ('formulation', models.CharField(blank=True, default='', max_length=100, verbose_name='剤型')),
+                ('usage_unit', models.CharField(blank=True, default='', max_length=50, verbose_name='使用単位')),
+                ('dilution_ratio', models.CharField(blank=True, default='', max_length=100, verbose_name='希釈倍率')),
+                ('active_ingredient', models.CharField(blank=True, default='', max_length=200, verbose_name='有効成分')),
+                ('category', models.CharField(blank=True, default='', max_length=100, verbose_name='分類')),
+                ('material', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='pesticide_profile', to='materials.material')),
+            ],
+            options={
+                'verbose_name': '農薬詳細',
+                'verbose_name_plural': '農薬詳細',
+            },
+        ),
+        migrations.CreateModel(
+            name='StockTransaction',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('transaction_type', models.CharField(choices=[('purchase', '入庫'), ('use', '使用'), ('adjustment_plus', '棚卸増'), ('adjustment_minus', '棚卸減'), ('discard', '廃棄')], max_length=30, verbose_name='取引種別')),
+                ('quantity', models.DecimalField(decimal_places=3, max_digits=10, validators=[django.core.validators.MinValueValidator(decimal.Decimal('0.001'))], verbose_name='数量')),
+                ('occurred_on', models.DateField(verbose_name='発生日')),
+                ('note', models.TextField(blank=True, default='', verbose_name='備考')),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('material', models.ForeignKey(on_delete=django.db.models.deletion.PROTECT, related_name='stock_transactions', to='materials.material', verbose_name='資材')),
+            ],
+            options={
+                'verbose_name': '入出庫履歴',
+                'verbose_name_plural': '入出庫履歴',
+                'ordering': ['-occurred_on', '-created_at', '-id'],
+            },
+        ),
+        migrations.AddConstraint(
+            model_name='material',
+            constraint=models.UniqueConstraint(fields=('material_type', 'name'), name='uniq_material_type_name'),
+        ),
+    ]

backend/apps/materials/migrations/__init__.py

@@ -0,0 +1 @@
+