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/cachetools/_cachedmethod.py

@@ -0,0 +1,128 @@
+"""Method decorator helpers."""
+
+import functools
+import weakref
+
+
+def warn_cache_none():
+    from warnings import warn
+
+    warn(
+        "returning `None` from `cache(self)` is deprecated",
+        DeprecationWarning,
+        stacklevel=3,
+    )
+
+
+def _condition(method, cache, key, lock, cond):
+    pending = weakref.WeakKeyDictionary()
+
+    def wrapper(self, *args, **kwargs):
+        c = cache(self)
+        if c is None:
+            warn_cache_none()
+            return method(self, *args, **kwargs)
+        k = key(self, *args, **kwargs)
+        with lock(self):
+            p = pending.setdefault(self, set())
+            cond(self).wait_for(lambda: k not in p)
+            try:
+                return c[k]
+            except KeyError:
+                p.add(k)
+        try:
+            v = method(self, *args, **kwargs)
+            with lock(self):
+                try:
+                    c[k] = v
+                except ValueError:
+                    pass  # value too large
+                return v
+        finally:
+            with lock(self):
+                pending[self].remove(k)
+                cond(self).notify_all()
+
+    def cache_clear(self):
+        c = cache(self)
+        if c is not None:
+            with lock(self):
+                c.clear()
+
+    wrapper.cache_clear = cache_clear
+    return wrapper
+
+
+def _locked(method, cache, key, lock):
+    def wrapper(self, *args, **kwargs):
+        c = cache(self)
+        if c is None:
+            warn_cache_none()
+            return method(self, *args, **kwargs)
+        k = key(self, *args, **kwargs)
+        with lock(self):
+            try:
+                return c[k]
+            except KeyError:
+                pass  # key not found
+        v = method(self, *args, **kwargs)
+        # in case of a race, prefer the item already in the cache
+        with lock(self):
+            try:
+                return c.setdefault(k, v)
+            except ValueError:
+                return v  # value too large
+
+    def cache_clear(self):
+        c = cache(self)
+        if c is not None:
+            with lock(self):
+                c.clear()
+
+    wrapper.cache_clear = cache_clear
+    return wrapper
+
+
+def _unlocked(method, cache, key):
+    def wrapper(self, *args, **kwargs):
+        c = cache(self)
+        if c is None:
+            warn_cache_none()
+            return method(self, *args, **kwargs)
+        k = key(self, *args, **kwargs)
+        try:
+            return c[k]
+        except KeyError:
+            pass  # key not found
+        v = method(self, *args, **kwargs)
+        try:
+            c[k] = v
+        except ValueError:
+            pass  # value too large
+        return v
+
+    def cache_clear(self):
+        c = cache(self)
+        if c is not None:
+            c.clear()
+
+    wrapper.cache_clear = cache_clear
+    return wrapper
+
+
+def _wrapper(method, cache, key, lock=None, cond=None):
+    if cond is not None and lock is not None:
+        wrapper = _condition(method, cache, key, lock, cond)
+    elif cond is not None:
+        wrapper = _condition(method, cache, key, cond, cond)
+    elif lock is not None:
+        wrapper = _locked(method, cache, key, lock)
+    else:
+        wrapper = _unlocked(method, cache, key)
+
+    wrapper.cache = cache
+    wrapper.cache_key = key
+    wrapper.cache_lock = lock if lock is not None else cond
+    wrapper.cache_condition = cond
+
+    return functools.update_wrapper(wrapper, method)