feat: Implement Keywords management page with DataGrid

Frontend Phase 2 - Keywords Management:
- Add MainLayout component with sidebar navigation
- Implement Keywords page with MUI DataGrid
- Add Keywords CRUD operations (Create, Edit, Delete dialogs)
- Add search and filter functionality (Category, Status)
- Install @mui/x-data-grid package for table component
- Update routing to include Keywords page
- Update Dashboard to use MainLayout
- Add navigation menu items for all planned pages

Features implemented:
- Keywords list with DataGrid table
- Add/Edit keyword dialog with form validation
- Delete confirmation dialog
- Category filter (People, Topics, Companies)
- Status filter (Active, Inactive)
- Search functionality
- Priority management

Tested in browser:
- Page loads successfully
- API integration working (200 OK)
- Layout and navigation functional
- All UI components rendering correctly

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

services/news-engine-console/frontend/package.json

@@ -11,17 +11,18 @@
     "type-check": "tsc --noEmit"
   },
   "dependencies": {
+    "@emotion/react": "^11.13.3",
+    "@emotion/styled": "^11.13.0",
+    "@mui/icons-material": "^6.1.3",
+    "@mui/material": "^6.1.3",
+    "@mui/x-data-grid": "^8.16.0",
+    "@tanstack/react-query": "^5.56.2",
+    "axios": "^1.7.7",
+    "date-fns": "^4.1.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-router-dom": "^6.26.2",
-    "@mui/material": "^6.1.3",
-    "@mui/icons-material": "^6.1.3",
-    "@emotion/react": "^11.13.3",
-    "@emotion/styled": "^11.13.0",
-    "@tanstack/react-query": "^5.56.2",
-    "axios": "^1.7.7",
     "recharts": "^2.12.7",
-    "date-fns": "^4.1.0",
     "zustand": "^5.0.0"
   },
   "devDependencies": {