Remove generic CLI dispatch transport after wp-coding-agents owns runtime

[chubes4]

Summary

wp-coding-agents now owns the generic local CLI transport/runtime for agents/dispatch-message in Extra-Chill/wp-coding-agents#178.

Data Machine Code should stop carrying the generic transport substrate that was originally added in #412:

• DataMachineCode\\Channels\\CliChannelTransport
• DataMachineCode\\Channels\\CliChannelRegistry
• bootstrap registration from data-machine-code.php
• DMC-owned smoke coverage/docs for that generic runtime

Compatibility

wp-coding-agents#178 keeps reading the legacy datamachine_code_cli_channels registry as well as the new wp_coding_agents_cli_channels registry, so existing live bridge config can keep dispatching while DMC removes its runtime registration.

Acceptance criteria

• DMC no longer registers a generic agents/dispatch-message CLI transport handler.
• DMC keeps only DMC-specific channel contributions, if any exist.
• Existing installs using wp-coding-agents bridge config continue to dispatch through wp-coding-agents.

Related

• Own generic CLI channel transport for agents/dispatch-message instead of DMC wp-coding-agents#177
• Own CLI dispatch transport in wp-coding-agents wp-coding-agents#178
• feat(channels): generic CLI transport runtime for agents/dispatch-message #412