feat: add Zod validation schemas for all domain routes

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

src/schemas/roles.schema.ts

@@ -0,0 +1,17 @@
+import { z } from 'zod';
+
+export const CreateRoleSchema = z.object({
+  name: z.string().min(1, 'Název role je povinný'),
+  display_name: z.string().min(1, 'Zobrazovaný název je povinný'),
+  description: z.string().nullish(),
+  permission_ids: z.array(z.number()).optional(),
+});
+
+export const UpdateRoleSchema = z.object({
+  display_name: z.string().optional(),
+  description: z.string().optional(),
+  permission_ids: z.array(z.number()).optional(),
+});
+
+export type CreateRoleInput = z.infer<typeof CreateRoleSchema>;
+export type UpdateRoleInput = z.infer<typeof UpdateRoleSchema>;