[BUG] bridging 运行自己的会话也是会话：record seam 每小时挖掘自己的运行记录，prepare 永远不会为空（claude_code/hermes 已经验证）

The recommended fix — host-independent, and located in bridging/ — is to add a stable sentinel marker to the standard bridging prompt (in the host-specific BRIDGING_TASK.md file, and in the generated bridge-prompt.txt), and have prepare skip the session with that marker in the first user record.