feat(web): add web admin dashboard (React + Tailwind + TypeScript)

Full-featured management UI for CC-Connect instances:
- Token-based auth, dark/light/system theme, i18n (EN/ZH/ZH-TW/JA/ES)
- Dashboard with system status, project overview
- Project management with providers, heartbeat, settings tabs
- Session list and chat interface with Markdown rendering
- Cron job management (create/delete)
- Bridge adapter viewer
- System config viewer, logs, restart/reload controls
- All endpoints aligned with docs/management-api.md

Made-with: Cursor

web/node_modules/tailwindcss

@@ -0,0 +1 @@
+.pnpm/tailwindcss@3.4.19/node_modules/tailwindcss