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/build/_util.py

@@ -0,0 +1,63 @@
+from __future__ import annotations
+
+import re
+
+from collections.abc import Iterator, Set
+
+
+_WHEEL_FILENAME_REGEX = re.compile(
+    r'(?P<distribution>.+)-(?P<version>.+)'
+    r'(-(?P<build_tag>.+))?-(?P<python_tag>.+)'
+    r'-(?P<abi_tag>.+)-(?P<platform_tag>.+)\.whl'
+)
+
+
+def check_dependency(
+    req_string: str, ancestral_req_strings: tuple[str, ...] = (), parent_extras: Set[str] = frozenset()
+) -> Iterator[tuple[str, ...]]:
+    """
+    Verify that a dependency and all of its dependencies are met.
+
+    :param req_string: Requirement string
+    :param parent_extras: Extras (eg. "test" in myproject[test])
+    :yields: Unmet dependencies
+    """
+    import packaging.requirements
+
+    from ._compat import importlib
+
+    req = packaging.requirements.Requirement(req_string)
+    normalised_req_string = str(req)
+
+    # ``Requirement`` doesn't implement ``__eq__`` so we cannot compare reqs for
+    # equality directly but the string representation is stable.
+    if normalised_req_string in ancestral_req_strings:
+        # cyclical dependency, already checked.
+        return
+
+    if req.marker:
+        extras = frozenset(('',)).union(parent_extras)
+        # a requirement can have multiple extras but ``evaluate`` can
+        # only check one at a time.
+        if all(not req.marker.evaluate(environment={'extra': e}) for e in extras):
+            # if the marker conditions are not met, we pretend that the
+            # dependency is satisfied.
+            return
+
+    try:
+        dist = importlib.metadata.distribution(req.name)
+    except importlib.metadata.PackageNotFoundError:
+        # dependency is not installed in the environment.
+        yield (*ancestral_req_strings, normalised_req_string)
+    else:
+        if req.specifier and not req.specifier.contains(dist.version, prereleases=True):
+            # the installed version is incompatible.
+            yield (*ancestral_req_strings, normalised_req_string)
+        elif dist.requires:
+            for other_req_string in dist.requires:
+                # yields transitive dependencies that are not satisfied.
+                yield from check_dependency(other_req_string, (*ancestral_req_strings, normalised_req_string), req.extras)
+
+
+def parse_wheel_filename(filename: str) -> re.Match[str] | None:
+    return _WHEEL_FILENAME_REGEX.match(filename)