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/uvloop/includes/consts.pxi

@@ -0,0 +1,33 @@
+cdef enum:
+    UV_STREAM_RECV_BUF_SIZE = 256000  # 250kb
+
+    FLOW_CONTROL_HIGH_WATER = 64  # KiB
+    FLOW_CONTROL_HIGH_WATER_SSL_READ = 256  # KiB
+    FLOW_CONTROL_HIGH_WATER_SSL_WRITE = 512  # KiB
+
+    DEFAULT_FREELIST_SIZE = 250
+    DNS_PYADDR_TO_SOCKADDR_CACHE_SIZE = 2048
+
+    DEBUG_STACK_DEPTH = 10
+
+
+    __PROCESS_DEBUG_SLEEP_AFTER_FORK = 1
+
+
+    LOG_THRESHOLD_FOR_CONNLOST_WRITES = 5
+    SSL_READ_MAX_SIZE = 256 * 1024
+
+
+cdef extern from *:
+    '''
+    // Number of seconds to wait for SSL handshake to complete
+    // The default timeout matches that of Nginx.
+    #define SSL_HANDSHAKE_TIMEOUT 60.0
+
+    // Number of seconds to wait for SSL shutdown to complete
+    // The default timeout mimics lingering_time
+    #define SSL_SHUTDOWN_TIMEOUT 30.0
+    '''
+
+    const float SSL_HANDSHAKE_TIMEOUT
+    const float SSL_SHUTDOWN_TIMEOUT