feat: add CLI Viewer Page with multi-pane layout and state management

- Implemented the CliViewerPage component for displaying CLI outputs in a configurable multi-pane layout.
- Integrated Zustand for state management, allowing for dynamic layout changes and tab management.
- Added layout options: single, split horizontal, split vertical, and 2x2 grid.
- Created viewerStore for managing layout, panes, and tabs, including actions for adding/removing panes and tabs.
- Added CoordinatorPage barrel export for easier imports.

ccw/frontend/src/locales/en/cli-monitor.json

@@ -45,5 +45,7 @@
   "tokens": "Tokens: {count}",
   "duration": "Duration: {value}",
   "model": "Model: {name}",
-  "user": "User"
+  "user": "User",
+  "popOutToPage": "Open in Full Page",
+  "openInViewer": "Open in CLI Viewer"
 }