fix: bulk attendance fill — accept string user_ids, skip holidays

- Schema now accepts both string and number user_ids (frontend sends strings)
- Bulk fill now skips Czech public holidays in addition to weekends

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

src/schemas/attendance.schema.ts

@@ -39,7 +39,9 @@ export const AttendanceBalancesSchema = z.object({
 
 export const AttendanceBulkSchema = z.object({
   month: z.string().regex(/^\d{4}-\d{2}$/, "Měsíc je povinný (formát YYYY-MM)"),
-  user_ids: z.array(z.number()).min(1, "Vyberte alespoň jednoho zaměstnance"),
+  user_ids: z
+    .array(z.union([z.number(), z.string()]).transform((v) => Number(v)))
+    .min(1, "Vyberte alespoň jednoho zaměstnance"),
   arrival_time: z.string().optional().default("08:00"),
   departure_time: z.string().optional().default("16:30"),
   break_start_time: z.string().optional().default("12:00"),