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/mosaic/src/cli.ts

@@ -3,6 +3,7 @@
 import { createRequire } from 'module';
 import { Command } from 'commander';
 import { registerBrainCommand } from '@mosaicstack/brain';
+import { registerMacpCommand } from '@mosaicstack/macp';
 import { registerQualityRails } from '@mosaicstack/quality-rails';
 import { registerQueueCommand } from '@mosaicstack/queue';
 import { registerAgentCommand } from './commands/agent.js';
@@ -344,6 +345,10 @@ registerMissionCommand(program);
 
 registerBrainCommand(program);
 
+// ─── macp ────────────────────────────────────────────────────────────────
+
+registerMacpCommand(program);
+
 // ─── quality-rails ──────────────────────────────────────────────────────
 
 registerQualityRails(program);