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/quarterly_ticker_bbca.json

@@ -0,0 +1,10 @@
+[
+ {
+  "report_date": "2026-07-28",
+  "quarter": "q2"
+ },
+ {
+  "report_date": "2026-04-28",
+  "quarter": "q1"
+ }
+]