feat(cli): add mosaic gateway init command with tier selection wizard

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

packages/cli/src/cli.ts

@@ -7,6 +7,7 @@ import { registerAgentCommand } from './commands/agent.js';
 import { registerMissionCommand } from './commands/mission.js';
 // prdy is registered via launch.ts
 import { registerLaunchCommands } from './commands/launch.js';
+import { registerGatewayCommand } from './commands/gateway.js';
 
 const _require = createRequire(import.meta.url);
 const CLI_VERSION: string = (_require('../package.json') as { version: string }).version;
@@ -290,6 +291,10 @@ sessionsCmd
     }
   });
 
+// ─── gateway ──────────────────────────────────────────────────────────
+
+registerGatewayCommand(program);
+
 // ─── agent ─────────────────────────────────────────────────────────────
 
 registerAgentCommand(program);