Fix: Ensure UTF-8 encoding for all file operations

nanobot/cron/service.py

@@ -66,7 +66,7 @@ class CronService:
         
         if self.store_path.exists():
             try:
-                data = json.loads(self.store_path.read_text())
+                data = json.loads(self.store_path.read_text(encoding="utf-8"))
                 jobs = []
                 for j in data.get("jobs", []):
                     jobs.append(CronJob(
@@ -148,7 +148,7 @@ class CronService:
             ]
         }
         
-        self.store_path.write_text(json.dumps(data, indent=2))
+        self.store_path.write_text(json.dumps(data, indent=2, ensure_ascii=False), encoding="utf-8")
     
     async def start(self) -> None:
         """Start the cron service."""