P2: Mark adapter template private or make publish config consistent

[vamgan]

Problem

Template release docs say this package is a private template and should not be published, but package.json contains public publish settings and package files.

Relevant files:

• docs/release.md
• package.json

The template package also lacks an exports map unlike the real adapter packages.

Impact

Accidental public publish is easier, and if published, import ergonomics may differ from other AgentDispatch packages.

Suggested fix

If private: add "private": true and remove public publishConfig.

If intended to be publishable: add an exports map consistent with other packages and update release docs.

Acceptance criteria

• Package metadata matches intended lifecycle.
• Release docs no longer conflict with package config.