feat: add Edit button to each row in Missing Data view

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/App.tsx

@@ -566,6 +566,7 @@ export default function App() {
                 <MissingDataView
                   data={appState.data}
                   headers={appState.headers}
+                  onEdit={(index) => setEditingRowIndex(index)}
                 />
               )}
               {activeModule === 'history' && (