feat: add back_design field to Project model

backend/apps/projects/migrations/0004_project_back_design.py

@@ -0,0 +1,19 @@
+# Generated by Django 5.1.4 on 2026-06-03 13:58
+
+import apps.projects.models
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('projects', '0003_libraryasset'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='project',
+            name='back_design',
+            field=models.JSONField(default=apps.projects.models.default_back_design),
+        ),
+    ]

backend/apps/projects/models.py

@@ -36,6 +36,20 @@ def default_card_overrides():
     }
 
 
+def default_back_design():
+    """背面专用设计配置（独立于正面）"""
+    return {
+        'background_color': '#1A237E',
+        'border_color': '#C0A050',
+        'border_width': 3,
+        'pattern_color': None,
+        'image': None,
+        'image_dx': 0,
+        'image_dy': 0,
+        'image_scale': 1,
+    }
+
+
 class Project(models.Model):
     """项目配置模型"""
     id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
@@ -47,6 +61,8 @@ class Project(models.Model):
     design = models.JSONField(default=default_design)
     # 每张牌对项目级配置的覆盖
     card_overrides = models.JSONField(default=default_card_overrides)
+    # 背面专用设计配置（独立于正面 design）
+    back_design = models.JSONField(default=default_back_design)
     # 数字牌花色位置微调（相对 0~1）
     # { '1': [{'dx':0,'dy':0,'scale':1}, ...], '2': [...], ... }
     number_layout = models.JSONField(default=dict)