fix: remove Reference section from docs sidebar

The Reference section was referencing files that don't exist in the
repository (they only exist locally). Removed the entire Reference
section from the Astro sidebar config to fix the Deploy Docs workflow.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: ndbroadbent

docs/astro.config.mjs

@@ -277,19 +277,6 @@ export default defineConfig({
             { label: 'API Reference', slug: 'development/api-reference' },
           ],
         },
-        {
-          label: 'Reference',
-          items: [
-            { label: 'CLI Commands', slug: 'reference/cli-commands' },
-            {
-              label: 'Environment Variables',
-              slug: 'reference/environment-variables',
-            },
-            { label: 'RBAC Permissions', slug: 'reference/rbac-permissions' },
-            { label: 'Audit Events', slug: 'reference/audit-events' },
-            { label: 'API Endpoints', slug: 'reference/api-endpoints' },
-          ],
-        },
       ],
     }),
   ],