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

lib/validate.ts

@@ -0,0 +1,88 @@
+import type { RecordType } from "./db"
+
+export type FieldErrors = Record<string, string>
+
+export interface RecordInput {
+  domain: string
+  type: RecordType
+  value: string
+  enabled: boolean
+  comment: string
+}
+
+export type ParseResult =
+  | { ok: true; input: RecordInput }
+  | { ok: false; fieldErrors: FieldErrors }
+
+const LABEL = /^[a-z0-9]([a-z0-9-]*[a-z0-9])?$/
+
+/** Lowercase, trim surrounding space and drop a trailing dot (`nas.home.` -> `nas.home`). */
+export function normalizeDomain(raw: string): string {
+  return raw
+    .trim()
+    .toLowerCase()
+    .replace(/\.+$/, "")
+}
+
+export function isValidDomain(domain: string): boolean {
+  if (!domain || domain.length > 253) return false
+  const labels = domain.split(".")
+  if (labels.length === 0) return false
+  return labels.every((label) => label.length > 0 && label.length <= 63 && LABEL.test(label))
+}
+
+export function isValidIPv4(value: string): boolean {
+  const parts = value.trim().split(".")
+  if (parts.length !== 4) return false
+  return parts.every((part) => /^\d{1,3}$/.test(part) && Number(part) <= 255)
+}
+
+function readText(formData: FormData, key: string): string {
+  const value = formData.get(key)
+  return typeof value === "string" ? value.trim() : ""
+}
+
+/**
+ * Validate a submitted record form. Used by both the create/update Server Actions and the
+ * resolve page, so every user-supplied domain goes through the same rules.
+ */
+export function parseRecordForm(formData: FormData): ParseResult {
+  const fieldErrors: FieldErrors = {}
+
+  const domain = normalizeDomain(readText(formData, "domain"))
+  if (!domain) {
+    fieldErrors.domain = "请填写域名"
+  } else if (!isValidDomain(domain)) {
+    fieldErrors.domain = "域名格式不正确，例如 nas.home"
+  }
+
+  const rawType = readText(formData, "type")
+  const type: RecordType = rawType === "CNAME" ? "CNAME" : "A"
+
+  const value = normalizeDomain(readText(formData, "value"))
+  if (!value) {
+    fieldErrors.value = "请填写目标值"
+  } else if (type === "A") {
+    if (!isValidIPv4(value)) fieldErrors.value = "A 记录的目标必须是 IPv4 地址"
+  } else if (!isValidDomain(value)) {
+    fieldErrors.value = "CNAME 的目标必须是域名"
+  } else if (value === domain) {
+    fieldErrors.value = "CNAME 的目标不能指向自己"
+  }
+
+  const comment = readText(formData, "comment")
+  if (comment.length > 200) fieldErrors.comment = "备注请控制在 200 字以内"
+
+  if (Object.keys(fieldErrors).length > 0) return { ok: false, fieldErrors }
+
+  return {
+    ok: true,
+    input: {
+      domain,
+      type,
+      value,
+      enabled: formData.get("enabled") !== null,
+      comment,
+    },
+  }
+}