Detailed Description

Module entry point for ``python -m oc_chat.registry``.

Purpose
-------
Provide the pre-M3 registry command path requested by plan 081.

Responsibilities
----------------
- Dispatch module execution to :func:`oc_chat.registry.cli.agent.main`.
- Preserve the CLI return code as the process exit code.

Diagnostics
-----------
Domain: OC_CHAT.MAIN
Levels:
    L2 - lifecycle events
    L3 - semantic details
    L4 - deep tracing

Contracts
---------
- This module contains no command implementation; it is only an entry point.

Dependencies
------------
- oc_diagnostics (structured debug logging via _dbg)
- oc_chat.registry.cli.agent (argparse command implementation)