refactor: SDK 包结构——transports/firmware 分包、bridge_server 入包+ppclock-bridge 入口、fw 工具入 SDK 域，151 测试全绿

pyproject.toml

@@ -17,6 +17,7 @@ dev = ["pytest>=8"]
 
 [project.scripts]
 ppclock = "ppclock.cli:main"
+ppclock-bridge = "ppclock.bridge_server:run"
 
 [tool.setuptools.packages.find]
 where = ["src"]