refactor: 后端代码清理-移除死代码和无用文件

- 删除 packages/domain/permissions.py（完全未引用的权限模块）
- 删除 packages/adapters/sqlite_tracker/（空包，无实现文件）
- 移除 requirements.txt 中未使用的依赖：aiosmtplib、python-dotenv
- 清理 test_email_service.py 中 workspace 邀请邮件的废弃测试

packages/adapters/sqlite_tracker/__init__.py

@@ -1,7 +0,0 @@
-"""SQLite Tracker Adapter"""
-
-__all__ = [
-    "SQLiteTaskRepository",
-    "SQLiteMilestoneRepository",
-    "SQLiteTaskIssueRepository",
-]

packages/domain/permissions.py

@@ -1,50 +0,0 @@
-"""
-Permissions module.
-All permission checks pass by default (workspace concept removed).
-"""
-
-
-class PermissionChecker:
-    """Permission checker - all checks pass by default."""
-
-    def __init__(self, member_repository=None):
-        self.member_repository = member_repository
-
-    def check_access(self, project_id, user_id):
-        return True, "owner"
-
-    def check_is_owner(self, project_id, user_id):
-        return True
-
-    def check_is_admin_or_owner(self, project_id, user_id):
-        return True
-
-    def check_can_manage_members(self, project_id, user_id):
-        return True
-
-    def check_can_edit_project(self, project_id, user_id):
-        return True
-
-    def check_can_delete_project(self, project_id, user_id):
-        return True
-
-    def check_can_view_project(self, project_id, user_id):
-        return True
-
-
-class Permission:
-    PROJECT_VIEW = "project:view"
-    PROJECT_CREATE = "project:create"
-    PROJECT_EDIT = "project:edit"
-    PROJECT_DELETE = "project:delete"
-    ASSET_VIEW = "asset:view"
-    ASSET_UPLOAD = "asset:upload"
-    ASSET_EDIT = "asset:edit"
-    ASSET_DELETE = "asset:delete"
-
-
-ROLE_PERMISSIONS = {}
-
-
-def has_permission(role, permission):
-    return True

requirements.txt

@@ -21,9 +21,6 @@ python-multipart==0.0.32
 # Redis
 redis==5.2.0
 
-# 邮件
-aiosmtplib==3.0.2
-
 # HTTP 客户端
 httpx==0.27.2
 
@@ -32,9 +29,6 @@ pytest==8.3.3
 pytest-asyncio==0.24.0
 pytest-cov==6.0.0
 
-# 工具
-python-dotenv==1.0.1
-
 # 视频处理
 ffmpeg-python==0.2.0
 Pillow==10.4.0

tests/unit/test_email_service.py

@@ -137,30 +137,6 @@ class TestEmailService:
         # 验证收件人
         assert call_args[0][1] == ["user@example.com"]
 
-    @patch("smtplib.SMTP")
-    def test_send_workspace_invitation_email(self, mock_smtp, email_service):
-        """测试发送工作空间邀请邮件"""
-        mock_server = MagicMock()
-        mock_smtp.return_value.__enter__.return_value = mock_server
-
-        success, error = email_service.send_workspace_invitation_email(
-            to_email="user@example.com",
-            inviter_name="Alice",
-            workspace_name="My Workspace",
-            role="admin",
-            invitation_url="https://example.com/invite?token=inv123",
-        )
-
-        assert success is True
-        assert error is None
-
-        # 验证发送了邮件
-        mock_server.sendmail.assert_called_once()
-        call_args = mock_server.sendmail.call_args
-
-        # 验证收件人
-        assert call_args[0][1] == ["user@example.com"]
-
     @patch("smtplib.SMTP")
     def test_email_without_tls(self, mock_smtp):
         """测试不使用 TLS 发送邮件"""