Erwartetes Serverformat
/server/calendar/{user}/YYYY-MM.json
{
"user": "frank",
"year": 2026,
"month": 1,
"counts": { "TS": 8, "NS": 8, "ST": 0, "U": 1, "FS": 5, "AFZ": 0, "BU": 0, "KR": 0 },
"hours": { "night": 64, "sunday": 19, "holiday": 12, "sfn_12": 95, "sfn_107143": 10.7143 }
}