Feat: support agent version history. (#6130)

### What problem does this PR solve?
Add history version save
- Allows users to view and download agent files by version revision
history

![image](https://github.com/user-attachments/assets/c300375d-8b97-4230-9fc4-83d148137132)

_Briefly describe what this PR aims to solve. Include background context
that will help reviewers understand the purpose of the PR._

### Type of change

- [ ] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
- [ ] Documentation Update
- [ ] Refactoring
- [ ] Performance Improvement
- [ ] Other (please describe):

---------

Co-authored-by: Kevin Hu <kevinhu.sh@gmail.com>

api/db/db_models.py

@@ -988,6 +988,16 @@ class CanvasTemplate(DataBaseModel):
     class Meta:
         db_table = "canvas_template"
 
+class UserCanvasVersion(DataBaseModel):
+    id = CharField(max_length=32, primary_key=True)
+    user_canvas_id = CharField(max_length=255, null=False, help_text="user_canvas_id", index=True)
+
+    title = CharField(max_length=255, null=True, help_text="Canvas title")
+    description = TextField(null=True, help_text="Canvas description")
+    dsl = JSONField(null=True, default={})
+
+    class Meta:
+        db_table = "user_canvas_version"
 
 def migrate_db():
     with DB.transaction():

api/db/services/user_canvas_version.py

@@ -0,0 +1,43 @@
+from api.db.db_models import UserCanvasVersion, DB
+from api.db.services.common_service import CommonService
+from peewee import DoesNotExist
+
+class UserCanvasVersionService(CommonService):
+    model = UserCanvasVersion
+    
+    
+    @classmethod
+    @DB.connection_context()
+    def list_by_canvas_id(cls, user_canvas_id):
+        try:
+            user_canvas_version = cls.model.select(
+                *[cls.model.id, 
+                cls.model.create_time,
+                cls.model.title,
+                cls.model.create_date, 
+                cls.model.update_date,
+                cls.model.user_canvas_id, 
+                cls.model.update_time]
+            ).where(cls.model.user_canvas_id == user_canvas_id)
+            return user_canvas_version
+        except DoesNotExist:
+            return None
+        except Exception:
+            return None
+    
+    @classmethod
+    @DB.connection_context()
+    def delete_all_versions(cls, user_canvas_id):
+        try:
+            user_canvas_version = cls.model.select().where(cls.model.user_canvas_id == user_canvas_id).order_by(cls.model.create_time.desc())
+            if user_canvas_version.count() > 20:
+                for i in range(20, user_canvas_version.count()):
+                    cls.delete(user_canvas_version[i].id)
+            return True
+        except DoesNotExist:
+            return None
+        except Exception:
+            return None
+
+
+