feat(forge): wire registerForgeCommand into mosaic root CLI

Adds import and registerForgeCommand(program) call to packages/mosaic/src/cli.ts,
completing the mosaic forge CLI surface for mission cli-unification-20260404 task CU-05-01.

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

packages/mosaic/src/cli.ts

@@ -2,6 +2,7 @@
 
 import { createRequire } from 'module';
 import { Command } from 'commander';
+import { registerForgeCommand } from '@mosaicstack/forge';
 import { registerQualityRails } from '@mosaicstack/quality-rails';
 import { registerMacpCommand } from '@mosaicstack/macp';
 import { registerAgentCommand } from './commands/agent.js';
@@ -319,6 +320,10 @@ registerMissionCommand(program);
 
 registerMacpCommand(program);
 
+// ─── forge ───────────────────────────────────────────────────────────────
+
+registerForgeCommand(program);
+
 // ─── quality-rails ──────────────────────────────────────────────────────
 
 registerQualityRails(program);