feat: replace global EditPanel with focused 3-field panel in Missing Data

When editing from Missing Data view, only Classification, Launch Date
and Ready to Order fields are shown in a lightweight slide-in panel.

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

src/App.tsx

@@ -566,7 +566,8 @@ export default function App() {
                 <MissingDataView
                   data={appState.data}
                   headers={appState.headers}
-                  onEdit={(index) => setEditingRowIndex(index)}
+                  onSaveRow={handleSaveRow}
+                  onCaptureState={captureState}
                 />
               )}
               {activeModule === 'history' && (