feat: 实现联系表单提交与邮件通知功能

添加联系表单提交接口和邮件通知功能，支持从环境变量读取 SMTP 配置
重构 SEO 配置到 site.json，新增 robots.txt 和 sitemap.xml 生成
更新公司电话并添加 PM2 生产运行配置

lib/contact-mailer-config.ts

@@ -0,0 +1,99 @@
+import { readFile } from "node:fs/promises"
+import path from "node:path"
+import { parse } from "yaml"
+import { z } from "zod"
+
+export const CONTACT_MAILER_CONFIG_PATH = path.join(
+  process.cwd(),
+  "config",
+  "contact-mailer.yaml"
+)
+
+export class ContactMailerConfigError extends Error {}
+
+function coerceBoolean(value: unknown) {
+  if (typeof value === "boolean") {
+    return value
+  }
+
+  if (typeof value === "string") {
+    const normalized = value.trim().toLowerCase()
+
+    if (normalized === "true") {
+      return true
+    }
+
+    if (normalized === "false") {
+      return false
+    }
+  }
+
+  return value
+}
+
+function resolveEnvPlaceholders(value: unknown): unknown {
+  if (typeof value === "string") {
+    return value.replace(/\$\{([A-Z0-9_]+)(?::([^}]*))?\}/gi, (_, envName: string, fallback?: string) => {
+      return process.env[envName] ?? fallback ?? ""
+    })
+  }
+
+  if (Array.isArray(value)) {
+    return value.map(resolveEnvPlaceholders)
+  }
+
+  if (value && typeof value === "object") {
+    return Object.fromEntries(
+      Object.entries(value).map(([key, nestedValue]) => [key, resolveEnvPlaceholders(nestedValue)])
+    )
+  }
+
+  return value
+}
+
+const contactMailerConfigSchema = z.object({
+  smtp: z.object({
+    host: z.string().trim().min(1, "SMTP host 未配置"),
+    port: z.coerce.number().int().positive("SMTP port 未配置"),
+    secure: z.preprocess(coerceBoolean, z.boolean()),
+    auth: z.object({
+      user: z.string().trim().min(1, "SMTP 用户名未配置"),
+      pass: z.string().min(1, "SMTP 密码未配置"),
+    }),
+    from: z.object({
+      email: z.string().email("发件邮箱格式不正确"),
+      name: z.string().trim().min(1).default("智店软件官网"),
+    }),
+  }),
+  notification: z.object({
+    to: z.array(z.string().email("通知邮箱格式不正确")).min(1).default(["bd@zhidiansoft.com"]),
+    subjectPrefix: z.string().trim().min(1).default("官网线索"),
+  }).default({
+    to: ["bd@zhidiansoft.com"],
+    subjectPrefix: "官网线索",
+  }),
+})
+
+export type ContactMailerConfig = z.infer<typeof contactMailerConfigSchema>
+
+export async function loadContactMailerConfig() {
+  try {
+    const fileContent = await readFile(CONTACT_MAILER_CONFIG_PATH, "utf8")
+    const parsed = parse(fileContent) ?? {}
+    const resolved = resolveEnvPlaceholders(parsed)
+
+    return contactMailerConfigSchema.parse(resolved)
+  } catch (error) {
+    if (error instanceof z.ZodError) {
+      throw new ContactMailerConfigError(
+        `contact-mailer.yaml 配置不完整：${error.issues.map((issue) => issue.message).join("；")}`
+      )
+    }
+
+    if (error instanceof Error) {
+      throw new ContactMailerConfigError(`读取邮件配置失败：${error.message}`)
+    }
+
+    throw new ContactMailerConfigError("读取邮件配置失败")
+  }
+}