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/macp/package.json

@@ -21,6 +21,9 @@
     "typecheck": "tsc --noEmit",
     "test": "vitest run --passWithNoTests"
   },
+  "dependencies": {
+    "commander": "^13.0.0"
+  },
   "devDependencies": {
     "@types/node": "^22.0.0",
     "@vitest/coverage-v8": "^2.0.0",