feat: add invite code system and multi-image Drone pipeline

- Add InviteCode model with code, maxUses, expiry, usage tracking
- Registration now requires a valid invite code
- New users get USER role instead of ADMIN
- Admin-only /invites page to create, manage, and share invite codes
- Invite links auto-fill code via ?code= URL param
- Drone pipeline now builds app, worker, and bot images separately
- Add NEXT_PUBLIC_APP_URL build arg to fix URL redirects

src/app/(app)/invites/actions.ts

@@ -0,0 +1,54 @@
+"use server";
+
+import crypto from "crypto";
+import { auth } from "@/lib/auth";
+import { prisma } from "@/lib/prisma";
+import type { ActionResult } from "@/types/api.types";
+import { revalidatePath } from "next/cache";
+
+export async function createInviteCode(input: {
+  maxUses: number;
+  expiresInDays: number | null;
+}): Promise<ActionResult<{ code: string }>> {
+  const session = await auth();
+  if (!session?.user?.id || session.user.role !== "ADMIN") {
+    return { success: false, error: "Unauthorized" };
+  }
+
+  const code = crypto.randomBytes(6).toString("hex");
+  const expiresAt = input.expiresInDays
+    ? new Date(Date.now() + input.expiresInDays * 24 * 60 * 60 * 1000)
+    : null;
+
+  await prisma.inviteCode.create({
+    data: {
+      code,
+      maxUses: input.maxUses,
+      expiresAt,
+      createdBy: session.user.id,
+    },
+  });
+
+  revalidatePath("/invites");
+  return { success: true, data: { code } };
+}
+
+export async function deleteInviteCode(id: string): Promise<ActionResult> {
+  const session = await auth();
+  if (!session?.user?.id || session.user.role !== "ADMIN") {
+    return { success: false, error: "Unauthorized" };
+  }
+
+  await prisma.inviteCode.delete({ where: { id } });
+
+  revalidatePath("/invites");
+  return { success: true, data: undefined };
+}
+
+export async function getInviteCodes() {
+  const codes = await prisma.inviteCode.findMany({
+    orderBy: { createdAt: "desc" },
+    include: { creator: { select: { name: true } } },
+  });
+  return codes;
+}