Add email channel: IMAP IDLE inbound, SMTP outbound, thread matching

Inbound mail on support@top-sysops.ru creates/updates tickets in realtime
(IMAP IDLE, not polling). Replies thread via In-Reply-To/References against
stored Message-IDs, falling back to the customer's open ticket. Mailbox
credentials configured and encrypted via Settings -> Почта, same pattern as
the Telegram channel. TLS verification is opt-in-skippable per mailbox
(mail.top-sysops.ru's cert is currently expired; LAN-only server).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QcXH24ky6zjk2UyK5oZUPH

src/app/api/mailbox/config/route.ts

@@ -0,0 +1,62 @@
+export const runtime = "nodejs";
+
+import { NextResponse } from "next/server";
+import { z } from "zod";
+import { requireSession } from "@/lib/auth/require";
+import { getMailboxStatus } from "@/lib/mail/config";
+import { configureMailbox, disableMailListener } from "@/lib/mail/imap";
+import { verifySmtp } from "@/lib/mail/smtp";
+
+export async function GET() {
+  const { session, response } = await requireSession();
+  if (!session) return response;
+
+  return NextResponse.json(await getMailboxStatus());
+}
+
+const configureSchema = z.object({
+  host: z.string().min(1),
+  imapPort: z.coerce.number().int().positive(),
+  smtpPort: z.coerce.number().int().positive(),
+  user: z.string().email(),
+  password: z.string().min(1),
+  allowInsecureTls: z.boolean(),
+});
+
+export async function POST(request: Request) {
+  const { session, response } = await requireSession();
+  if (!session) return response;
+
+  const body = await request.json().catch(() => null);
+  const parsed = configureSchema.safeParse(body);
+  if (!parsed.success) {
+    return NextResponse.json({ error: "Invalid input" }, { status: 400 });
+  }
+
+  const settings = {
+    imapHost: parsed.data.host,
+    imapPort: parsed.data.imapPort,
+    smtpHost: parsed.data.host,
+    smtpPort: parsed.data.smtpPort,
+    user: parsed.data.user,
+    password: parsed.data.password,
+    allowInsecureTls: parsed.data.allowInsecureTls,
+  };
+
+  try {
+    await verifySmtp(settings);
+    await configureMailbox(settings);
+    return NextResponse.json({ ok: true });
+  } catch (err) {
+    const message = err instanceof Error ? err.message : "Unknown error";
+    return NextResponse.json({ error: `Не удалось подключиться: ${message}` }, { status: 400 });
+  }
+}
+
+export async function DELETE() {
+  const { session, response } = await requireSession();
+  if (!session) return response;
+
+  await disableMailListener();
+  return NextResponse.json({ ok: true });
+}