fix: resolve all lint errors from L4 feature

- Remove unused Box/Collapse from L4PortsApplyBanner
- Remove unused Stack from RedirectsFields
- Remove unused updateL4ProxyHost import from validation test
- Add eslint-disable-next-line for require() in vi.hoisted() blocks
  (necessary pattern since vi.hoisted runs before ESM imports)
- Add file-level eslint-disable no-explicit-any for test files that
  intentionally pass invalid types to test validation logic

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/l4-proxy-hosts/L4PortsApplyBanner.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useCallback, useEffect, useState } from "react";
-import { Alert, Box, Button, Chip, CircularProgress, Collapse, Stack, Typography } from "@mui/material";
+import { Alert, Button, Chip, CircularProgress, Stack, Typography } from "@mui/material";
 import SyncIcon from "@mui/icons-material/Sync";
 import CheckCircleIcon from "@mui/icons-material/CheckCircle";
 import ErrorIcon from "@mui/icons-material/Error";