feat: 接入 LogHive 远程日志系统

- 添加 LogHiveHandler，启动时自动挂载到 root logger
- 所有 logging 日志自动异步发送到 LogHive，不影响主业务
- vendored loghive-client 包，Docker 构建时自动安装
- API Key 缺失时自动跳过，不影响本地开发

vendor/setup.py

@@ -0,0 +1,23 @@
+"""Setup script for loghive-client."""
+
+from setuptools import setup, find_packages
+
+setup(
+    name="loghive-client",
+    version="0.1.0",
+    description="LogHive client SDK — push logs from your Python projects to LogHive",
+    author="LogHive",
+    packages=find_packages(),
+    install_requires=[
+        "httpx>=0.27.0",
+    ],
+    python_requires=">=3.10",
+    classifiers=[
+        "Development Status :: 3 - Alpha",
+        "Intended Audience :: Developers",
+        "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.10",
+        "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
+    ],
+)