Implement fullstack education catalog with disease detail pages, API routes, and shared types

- Add disease detail page component with data fetching and error handling
- Create shared types for diseases and classifications
- Implement API routes for diseases, classifications, and dashboard summary
- Develop reusable components for risk badge and disease card
- Build catalog page with search and filter functionality
- Update dashboard page with data-backed summary and manual classification form
- Register new routes in the web application
- Ensure type safety and consistency across shared modules

packages/shared/src/index.ts

@@ -1,2 +1,23 @@
 export type { AppStatus } from './app-status';
 export { createAppStatus } from './app-status';
+
+export type {
+  DiseaseLabel,
+  DiseaseSlug,
+  RiskLevel,
+  DiseaseCatalogItem,
+} from './diseases';
+export {
+  diseaseLabels,
+  diseaseSlugs,
+  riskLevels,
+  diseaseCatalogSeed,
+  isDiseaseSlug,
+  getDiseaseBySlug,
+} from './diseases';
+
+export type {
+  ManualClassificationRequest,
+  ManualClassificationRecord,
+  DashboardSummary,
+} from './classifications';