fix: add section header separator (=*80) to calendar_sync_api handler entry per INDEX.md logging convention

src/steps/advoware_cal_sync/calendar_sync_api_step.py

@@ -29,6 +29,9 @@ async def handler(request: ApiRequest, ctx: FlowContext) -> ApiResponse:
             "kuerzel": "SB"  // or "ALL" for all employees
         }
     """
+    ctx.logger.info("=" * 80)
+    ctx.logger.info("📥 CALENDAR SYNC API: REQUEST RECEIVED")
+    ctx.logger.info("=" * 80)
     try:
         # Get kuerzel from request body
         body = request.body