feat: add Citations and WatchlistChat components, integrate with API

- Implemented Citations component to display citation data.
- Created WatchlistDrawer and ChatSidebar components for managing watchlists and AI chat functionality.
- Integrated API calls for watchlist management and chat interactions.
- Updated index.tsx to include new components in the main application layout.
- Added API client in lib/api.ts for structured API interactions.
- Developed Alerts, Dashboard, Portfolio, Routines, Screener, and Report pages with relevant data fetching and UI components.
- Introduced styles in tokens.css for consistent theming across the application.
- Configured TypeScript and Vite for project setup and development.

backend/tests/fixtures/news_bbca.json

@@ -0,0 +1,31 @@
+{
+ "results": [
+  {
+   "title": "BBCA laba naik 18% didorong kredit korporasi",
+   "body": "laba naik rekor",
+   "source": "https://idx.example/a",
+   "timestamp": "2026-09-10T08:00:00Z",
+   "symbols": [
+    "BBCA"
+   ]
+  },
+  {
+   "title": "Analis upgrade BBCA, target tumbuh dua digit",
+   "body": "upgrade tumbuh positive",
+   "source": "https://idx.example/b",
+   "timestamp": "2026-09-11T08:00:00Z",
+   "symbols": [
+    "BBCA"
+   ]
+  },
+  {
+   "title": "BBCA umumkan jadwal RUPS tahunan",
+   "body": "jadwal rutin",
+   "source": "https://idx.example/c",
+   "timestamp": "2026-09-09T08:00:00Z",
+   "symbols": [
+    "BBCA"
+   ]
+  }
+ ]
+}