test: verify multi-chart management implementation

- Verified ChartSelector uses theme-aware classes
- Tested full workflow: upload, chart creation, switching, annotation scoping
- Verified migration creates default chart with existing data
- Tested chart deletion with cascade delete of candles/annotations
- Tested edge cases: duplicate filenames, deleting last chart, upload with no charts
- Build passes with no type errors

src/app/page.tsx

@@ -163,7 +163,7 @@ export default function Home() {
           <p className="text-sm text-muted-foreground mt-1">Chart annotation tool</p>
           <a
             href="/annotation-types"
-            className="mt-3 inline-block text-sm text-blue-600 hover:text-blue-800 underline"
+            className="mt-3 inline-block text-sm text-muted-foreground hover:text-foreground"
           >
             Manage Annotation Types
           </a>