feat: add dnsmasq DNS record admin UI

- store records in SQLite via built-in node:sqlite, no native deps
- wrap DB reads in await io() so they stay out of the static shell
- add CRUD pages backed by Server Actions with per-request data
- generate managed config and restart container via Docker socket
- add /resolve page to query dnsmasq for A and CNAME records
- add Dockerfile and compose setup with shared config volume

app/records/_components/ApplyButton.tsx

@@ -0,0 +1,37 @@
+"use client"
+
+import { useActionState } from "react"
+import type { ActionState } from "@/lib/action-state"
+
+export interface ApplyButtonProps {
+  action: (prev: ActionState, formData: FormData) => Promise<ActionState>
+}
+
+export function ApplyButton({ action }: ApplyButtonProps) {
+  const [state, formAction, pending] = useActionState<ActionState, FormData>(action, { ok: false })
+
+  return (
+    <div className="space-y-2">
+      <form action={formAction}>
+        <button
+          type="submit"
+          disabled={pending}
+          className="rounded-md bg-zinc-900 px-4 py-2 text-sm font-medium text-white transition-colors hover:bg-zinc-700 disabled:opacity-50 dark:bg-zinc-100 dark:text-zinc-900 dark:hover:bg-white">
+          {pending ? "应用中…" : "应用并重启 dnsmasq"}
+        </button>
+      </form>
+
+      {state.message ? (
+        <div className="space-y-1 text-sm">
+          <p
+            className={state.ok ? "text-emerald-700 dark:text-emerald-400" : "text-red-600 dark:text-red-400"}>
+            {state.message}
+          </p>
+          {state.detail ? (
+            <p className="text-xs text-zinc-500 dark:text-zinc-400">{state.detail}</p>
+          ) : null}
+        </div>
+      ) : null}
+    </div>
+  )
+}