feat: add domains, ideas, layouts, widgets API modules

- Add DomainsModule with full CRUD, search, and activity logging
- Add IdeasModule with quick capture endpoint
- Add LayoutsModule for user dashboard layouts
- Add WidgetsModule for widget definitions (read-only)
- Update ActivityService with domain/idea logging methods
- Register all new modules in AppModule

apps/web/src/components/widgets/index.ts

@@ -0,0 +1,8 @@
+/**
+ * Widget components
+ */
+
+export { TasksWidget } from "./TasksWidget";
+export { CalendarWidget } from "./CalendarWidget";
+export { QuickCaptureWidget } from "./QuickCaptureWidget";
+export { AgentStatusWidget } from "./AgentStatusWidget";