fix(web): clean up remaining Next.js artifacts in Vite migration

- Add vite-env.d.ts for import.meta.env and asset type declarations
- Remove dead layout.tsx (providers already in main.tsx)
- Fix useSearchParams destructuring to [searchParams] tuple (11 locations)
- Replace process.env.NEXT_PUBLIC_* with import.meta.env.VITE_*
- Fix langbotIcon.src to langbotIcon (Vite returns URL string)
- Fix Link href to Link to for react-router-dom
- Fix navigate({ scroll: false }) to { preventScrollReset: true }
- Fix [router] dependency arrays to [navigate]
- Remove Next.js plugin from tsconfig, set rsc: false in components.json
- Replace next lint with eslint in lint-staged

web/tsconfig.json

@@ -13,20 +13,13 @@
     "isolatedModules": true,
     "jsx": "react-jsx",
     "incremental": true,
-    "plugins": [
-      {
-        "name": "next"
-      }
-    ],
     "paths": {
       "@/*": ["./src/*"]
     }
   },
   "include": [
     "**/*.ts",
-    "**/*.tsx",
-    ".next/types/**/*.ts",
-    ".next/dev/types/**/*.ts"
+    "**/*.tsx"
   ],
   "exclude": ["node_modules"]
 }