feat(log): add registerLogCommand for mosaic log CLI surface

Adds mosaic log tail|search|export|level subcommands to @mosaicstack/log,
wires registerLogCommand into the root mosaic CLI, and ships a smoke test
that asserts command structure without opening the database. Ref CU-05-07.

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

packages/log/package.json

@@ -23,6 +23,7 @@
   },
   "dependencies": {
     "@mosaicstack/db": "workspace:*",
+    "commander": "^13.0.0",
     "drizzle-orm": "^0.45.1"
   },
   "devDependencies": {