chore: 添加虚拟环境到仓库

- 添加 backend_service/venv 虚拟环境
- 包含所有Python依赖包
- 注意：虚拟环境约393MB，包含12655个文件

backend_service/venv/lib/python3.13/site-packages/graphviz/jupyter_integration.py

@@ -0,0 +1,112 @@
+"""Display rendered graph as SVG in Jupyter Notebooks and QtConsole."""
+
+import typing
+
+from . import piping
+
+__all__ = ['JUPYTER_FORMATS',
+           'SUPPORTED_JUPYTER_FORMATS', 'DEFAULT_JUPYTER_FORMAT',
+           'get_jupyter_format_mimetype',
+           'JupyterIntegration']
+
+_IMAGE_JPEG = 'image/jpeg'
+
+JUPYTER_FORMATS = {'jpeg': _IMAGE_JPEG,
+                   'jpg': _IMAGE_JPEG,
+                   'png': 'image/png',
+                   'svg': 'image/svg+xml'}
+
+SUPPORTED_JUPYTER_FORMATS = set(JUPYTER_FORMATS)
+
+DEFAULT_JUPYTER_FORMAT = next(_ for _ in SUPPORTED_JUPYTER_FORMATS if _ == 'svg')
+
+MIME_TYPES = {'image/jpeg': '_repr_image_jpeg',
+              'image/png': '_repr_image_png',
+              'image/svg+xml': '_repr_image_svg_xml'}
+
+assert MIME_TYPES.keys() == set(JUPYTER_FORMATS.values())
+
+SVG_ENCODING = 'utf-8'
+
+
+def get_jupyter_format_mimetype(jupyter_format: str) -> str:
+    try:
+        return JUPYTER_FORMATS[jupyter_format]
+    except KeyError:
+        raise ValueError(f'unknown jupyter_format: {jupyter_format!r}'
+                         f' (must be one of {sorted(JUPYTER_FORMATS)})')
+
+
+def get_jupyter_mimetype_format(mimetype: str) -> str:
+    if mimetype not in MIME_TYPES:
+        raise ValueError(f'unsupported mimetype: {mimetype!r}'
+                         f' (must be one of {sorted(MIME_TYPES)})')
+
+    assert mimetype in JUPYTER_FORMATS.values()
+
+    for format, jupyter_mimetype in JUPYTER_FORMATS.items():
+        if jupyter_mimetype == mimetype:
+            return format
+
+    raise RuntimeError  # pragma: no cover
+
+
+class JupyterIntegration(piping.Pipe):
+    """Display rendered graph as SVG in Jupyter Notebooks and QtConsole."""
+
+    _jupyter_mimetype = get_jupyter_format_mimetype(DEFAULT_JUPYTER_FORMAT)
+
+    def _repr_mimebundle_(self,
+                          include: typing.Optional[typing.Iterable[str]] = None,
+                          exclude: typing.Optional[typing.Iterable[str]] = None,
+                          **_) -> typing.Dict[str, typing.Union[bytes, str]]:
+        r"""Return the rendered graph as IPython mimebundle.
+
+        Args:
+            include: Iterable of mimetypes to include in the result.
+                If not given or ``None``: ``['image/sxg+xml']``.
+            exclude: Iterable of minetypes to exclude from the result.
+                Overrides ``include``.
+
+        Returns:
+            Mapping from mimetypes to data.
+
+        Example:
+            >>> doctest_mark_exe()
+            >>> import graphviz
+            >>> dot = graphviz.Graph()
+            >>> dot._repr_mimebundle_()  # doctest: +ELLIPSIS
+            {'image/svg+xml': '<?xml version=...
+            >>> dot._repr_mimebundle_(include=['image/png'])  # doctest: +ELLIPSIS
+            {'image/png': b'\x89PNG...
+            >>> dot._repr_mimebundle_(include=[])
+            {}
+            >>> dot._repr_mimebundle_(include=['image/svg+xml', 'image/jpeg'],
+            ...                       exclude=['image/svg+xml'])  # doctest: +ELLIPSIS
+            {'image/jpeg': b'\xff...
+            >>> list(dot._repr_mimebundle_(include=['image/png', 'image/jpeg']))
+            ['image/jpeg', 'image/png']
+
+        See also:
+            IPython documentation:
+            - https://ipython.readthedocs.io/en/stable/api/generated/IPython.display.html#functions
+            - https://ipython.readthedocs.io/en/stable/config/integrating.html#MyObject._repr_mimebundle_  # noqa: E501
+            - https://nbviewer.org/github/ipython/ipython/blob/master/examples/IPython%20Kernel/Custom%20Display%20Logic.ipynb#Custom-Mimetypes-with-_repr_mimebundle_  # noqa: E501
+        """
+        include = set(include) if include is not None else {self._jupyter_mimetype}
+        include -= set(exclude or [])
+        return {mimetype: getattr(self, method_name)()
+                for mimetype, method_name in MIME_TYPES.items()
+                if mimetype in include}
+
+    def _repr_image_jpeg(self) -> bytes:
+        """Return the rendered graph as JPEG bytes."""
+        return self.pipe(format='jpeg')
+
+    def _repr_image_png(self) -> bytes:
+        """Return the rendered graph as PNG bytes."""
+        return self.pipe(format='png')
+
+    def _repr_image_svg_xml(self) -> str:
+        """Return the rendered graph as SVG string."""
+        return self.pipe(format='svg', encoding=SVG_ENCODING)