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/broker_summary_top_bbca.json

@@ -0,0 +1,39 @@
+{
+ "symbol": "BBCA.JK",
+ "start": "2026-09-07",
+ "end": "2026-09-11",
+ "origin": "all",
+ "cohort": "all",
+ "top_buyers": [
+  {
+   "rank": 1,
+   "broker_code": "MG",
+   "net_idr": 520000000000,
+   "buy_idr": 800000000000,
+   "sell_idr": 280000000000
+  },
+  {
+   "rank": 2,
+   "broker_code": "AK",
+   "net_idr": 410000000000,
+   "buy_idr": 700000000000,
+   "sell_idr": 290000000000
+  },
+  {
+   "rank": 3,
+   "broker_code": "CC",
+   "net_idr": 290000000000,
+   "buy_idr": 500000000000,
+   "sell_idr": 210000000000
+  }
+ ],
+ "top_sellers": [
+  {
+   "rank": 1,
+   "broker_code": "BK",
+   "net_idr": -180000000000,
+   "buy_idr": 200000000000,
+   "sell_idr": 380000000000
+  }
+ ]
+}