Implement Django backend and Vue frontend structure

- Django backend with projects, templates, exports apps
- SQLite database models for Project, Asset, CardLayer
- REST API endpoints for project management
- Vue frontend with Vite, Element Plus, Fabric.js
- Home page for project selection
- Editor page with Fabric.js canvas integration

backend/apps/projects/models.py

@@ -0,0 +1,56 @@
+from django.db import models
+import uuid
+
+class Project(models.Model):
+    """项目配置模型"""
+    id = models.UUIDField(primary_key=True, default=uuid.uuid4, editable=False)
+    name = models.CharField(max_length=100)
+    template_id = models.CharField(max_length=50, default='classic')
+    card_width = models.IntegerField(default=750)
+    card_height = models.IntegerField(default=1050)
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    # 导出设置
+    export_resolution = models.CharField(max_length=20, default='standard')
+    export_include_back = models.BooleanField(default=True)
+
+    def __str__(self):
+        return self.name
+
+    class Meta:
+        ordering = ['-updated_at']
+
+
+class Asset(models.Model):
+    """项目素材模型"""
+    asset_type = models.CharField(max_length=20)  # 'suit_symbol', 'face_card', 'joker', 'back', 'border'
+    asset_key = models.CharField(max_length=50)    # 如 'spade', 'heart-J', 'big_joker'
+    width = models.IntegerField(null=True)
+    height = models.IntegerField(null=True)
+    uploaded_at = models.DateTimeField(auto_now_add=True)
+
+    def __str__(self):
+        return f"{self.asset_type}:{self.asset_key}"
+
+
+class CardLayer(models.Model):
+    """牌面图层配置模型"""
+    card_type = models.CharField(max_length=20)  # 'number', 'face', 'joker'
+    card_key = models.CharField(max_length=30)   # 'spade-A', 'heart-K', 'big_joker'
+    layer_name = models.CharField(max_length=50)
+    layer_type = models.CharField(max_length=20)  # 'background', 'border', 'image', 'text'
+    visible = models.BooleanField(default=True)
+    locked = models.BooleanField(default=False)
+    opacity = models.FloatField(default=1.0)
+    z_index = models.IntegerField(default=0)
+
+    # 图层属性（JSON存储）
+    properties = models.JSONField(default=dict)
+    file_ref = models.ForeignKey(Asset, on_delete=models.SET_NULL, null=True, related_name='layers')
+
+    def __str__(self):
+        return f"{self.card_key}-{self.layer_name}"
+
+    class Meta:
+        ordering = ['card_key', 'z_index']