Refactor dashboard navigation, catalog grid, and API client

- Add sidebar dashboard navigation and support multiple dashboards
- Extract catalog grid/form logic to reusable CatalogsGrid component
- Add CatalogApiClient and DTOs for catalog CRUD operations
- Define dashboards with JSON data sources (Default, CatalogsGrid)
- Update configuration for dashboard and API endpoints
- Improve styling and imports for modularity and maintainability

DbFirst.API/appsettings.json

@@ -2,6 +2,9 @@
   "ConnectionStrings": {
     "DefaultConnection": "Server=SDD-VMP04-SQL17\\DD_DEVELOP01;Database=DD_ECM;User Id=sa;Password=dd;TrustServerCertificate=True;"
   },
+  "Dashboard": {
+    "BaseUrl": "https://localhost:7204"
+  },
   "Cors": {
     "AllowedOrigins": [
       "https://localhost:7276",