fix: resolve TypeScript compilation errors from service extraction

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/services/orders.service.ts

@@ -1,7 +1,7 @@
 import prisma from '../config/database';
 import { generateSharedNumber } from './numbering.service';
 
-interface OrderItemInput { description?: string; item_description?: string; quantity?: number; unit?: string; unit_price?: number; is_included_in_total?: boolean; position?: number }
+interface OrderItemInput { description?: string | null; item_description?: string | null; quantity?: number; unit?: string | null; unit_price?: number; is_included_in_total?: boolean; position?: number }
 interface OrderSectionInput { title?: string; title_cz?: string; content?: string; position?: number }
 
 // Status transition rules matching PHP

src/services/projects.service.ts

@@ -39,7 +39,7 @@ export async function listProjects(params: ListProjectsParams) {
     ...p,
     customer_name: p.customers?.name || null,
     responsible_user_name: p.users ? `${p.users.first_name} ${p.users.last_name}`.trim() : null,
-    order_number: p.orders?.[0]?.order_number || null,
+    order_number: (p.orders as any)?.order_number || null,
   }));
 
   return { data: enriched, total, page, limit };