main.tsx wraps the app in DemoProvider > MetadataProvider, but the
app.test.tsx render helpers only wrapped with DemoProvider. Since
e490d91 added useMetadata() to Sidebar, the routed app threw
"useMetadataContext must be used within MetadataProvider" in tests;
the error boundary swallowed the tree and the first-load assertion
failed. CI has been red on main since that commit.
Mirror the production provider nesting in both render sites.
1094904a03