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/components/layout/mobile-sidebar.tsx

@@ -15,13 +15,14 @@ import {
   Building2,
   MapPin,
   Settings,
+  UserPlus,
   Flame,
 } from "lucide-react";
 import { cn } from "@/lib/utils";
 import { APP_NAME, NAV_ITEMS } from "@/lib/constants";
 import { SheetHeader, SheetTitle } from "@/components/ui/sheet";
 
-const icons = { LayoutDashboard, Cylinder, Droplets, Paintbrush, Gem, FileBox, Send, ClipboardList, Building2, MapPin, Settings };
+const icons = { LayoutDashboard, Cylinder, Droplets, Paintbrush, Gem, FileBox, Send, ClipboardList, Building2, MapPin, Settings, UserPlus };
 
 export function MobileSidebar() {
   const pathname = usePathname();