fix: make API Docs page scrollable

LayoutShell's <main> sets overflow:hidden + min-height:0; pages must
handle their own scroll. SwaggerPage's root div had no height constraint,
so the Swagger UI rendered below the viewport with no scrollbar.

Match the pattern used by AppsTab/DashboardTab/etc.: flex:1 + min-height:0
+ overflow-y:auto on the page root. Inline style since this is a leaf
page with no existing module.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/src/pages/Swagger/SwaggerPage.tsx

@@ -29,7 +29,7 @@ export default function SwaggerPage() {
   }, [token]);
 
   return (
-    <div>
+    <div style={{ flex: 1, minHeight: 0, overflowY: 'auto', padding: '1rem 1.5rem' }}>
       <h2 style={{ marginBottom: '1rem' }}>API Documentation</h2>
       <div ref={containerRef} />
     </div>