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/package.json

@@ -19,9 +19,11 @@
     "@mosaic/ui": "workspace:*",
     "@tanstack/react-query": "^5.90.20",
     "date-fns": "^4.1.0",
+    "lucide-react": "^0.563.0",
     "next": "^16.1.6",
     "react": "^19.0.0",
-    "react-dom": "^19.0.0"
+    "react-dom": "^19.0.0",
+    "react-grid-layout": "^2.2.2"
   },
   "devDependencies": {
     "@mosaic/config": "workspace:*",
@@ -31,6 +33,7 @@
     "@types/node": "^22.13.4",
     "@types/react": "^19.0.8",
     "@types/react-dom": "^19.0.3",
+    "@types/react-grid-layout": "^2.1.0",
     "@vitejs/plugin-react": "^4.3.4",
     "@vitest/coverage-v8": "^3.2.4",
     "jsdom": "^26.0.0",