docs(cli): add dashboard action-reference check to os build step output

The `os build` sample output in cli.mdx enumerates each compile step; the new
ADR-0049 dashboard action-reference check landed between the widget-binding and
SDUI-styling steps, so list it there too. Addresses the docs-drift advisory on
#3383. Docs-only.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018KSiJuXDAi78CQD3Lv2TNJ

Author: claude

content/docs/getting-started/cli.mdx

@@ -379,6 +379,7 @@ os compile --json                    # JSON output for CI pipelines
   → Validating protocol compliance...
   → Validating expressions (ADR-0032)...
   → Checking dashboard widget bindings (ADR-0021)...
+  → Checking dashboard action references (ADR-0049)...
   → Checking SDUI styling (ADR-0065)...
   → Checking security posture (ADR-0090 D7)...
   → Collecting package docs (ADR-0046)...