feat(macp): add registerMacpCommand for mosaic macp CLI surface

Adds mosaic macp tasks list|submit|gate|events tail subcommands to
@mosaicstack/macp, wires registerMacpCommand into the root mosaic CLI,
and ships a smoke test asserting command structure without touching disk
or starting an event emitter. Ref CU-05-08.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/forge/src/index.ts

@@ -80,3 +80,6 @@ export {
   resumePipeline,
   getPipelineStatus,
 } from './pipeline-runner.js';
+
+// CLI
+export { registerForgeCommand } from './cli.js';