feat(app): add cross-workspace app sharing backend

api/app/models/appshare_model.py

@@ -1,6 +1,6 @@
 import datetime
 import uuid
-from sqlalchemy import Column, DateTime, ForeignKey
+from sqlalchemy import Column, DateTime, ForeignKey, String
 from sqlalchemy.dialects.postgresql import UUID
 from app.db import Base
 from sqlalchemy.orm import relationship
@@ -18,6 +18,7 @@ class AppShare(Base):
     source_workspace_id = Column(UUID(as_uuid=True), ForeignKey('workspaces.id'), nullable=False, comment="源工作空间ID")
     target_workspace_id = Column(UUID(as_uuid=True), ForeignKey('workspaces.id'), nullable=False, comment="目标工作空间ID")
     shared_by = Column(UUID(as_uuid=True), ForeignKey('users.id'), nullable=False, comment="分享者用户ID")
+    permission = Column(String, default="readonly", nullable=False, comment="权限模式: readonly | editable")
     created_at = Column(DateTime, default=datetime.datetime.now)
     updated_at = Column(DateTime, default=datetime.datetime.now)