Polish chat UI and wire flue agent env

- Add chat components (header, composer, conversation, message, thinking response, identity)
- Add chat hooks (use-chat-agent, use-chat-composer)
- Add chat lib (constants, transforms, types)
- Wire agent model config through env (provider, name, api, base url, key, context window, max tokens)
- Refresh web styling and routes

apps/web/package.json

@@ -5,6 +5,7 @@
   "scripts": {
     "build": "react-router build",
     "dev": "react-router dev",
+    "dev:tailscale": "react-router dev --host 0.0.0.0",
     "start": "react-router-serve ./build/server/index.js",
     "typecheck": "react-router typegen && tsc"
   },
@@ -13,6 +14,8 @@
     "@code/env": "workspace:*",
     "@code/ui": "workspace:*",
     "@convex-dev/better-auth": "catalog:",
+    "@flue/react": "1.0.0-beta.9",
+    "@flue/sdk": "1.0.0-beta.9",
     "@react-router/fs-routes": "^8.1.0",
     "@react-router/node": "^8.1.0",
     "@react-router/serve": "^8.1.0",
@@ -26,6 +29,7 @@
     "react-dom": "^19.2.7",
     "react-router": "^8.1.0",
     "sonner": "catalog:",
+    "streamdown": "2.5.0",
     "zod": "catalog:"
   },
   "devDependencies": {