feat: refresh accounts automatically every five minutes

backend/internal/app/api.go

@@ -408,9 +408,9 @@ func (a *App) logout(w http.ResponseWriter, r *http.Request) {
 func (a *App) general() GeneralSettings {
 	g := defaults()
 	a.store.GetJSON("general", &g)
-	if g.SyncMinutes < 1 {
-		g.SyncMinutes = 5
-	}
+	// Keep the legacy field in the response for old clients, but automatic
+	// account synchronization is intentionally fixed at five minutes.
+	g.SyncMinutes = automaticSyncMinutes
 	if g.RetentionDays < 1 {
 		g.RetentionDays = 90
 	}
@@ -430,6 +430,7 @@ func (a *App) generalAPI(w http.ResponseWriter, r *http.Request) {
 		jsonOut(w, 400, map[string]string{"error": "无效时区"})
 		return
 	}
+	g.SyncMinutes = automaticSyncMinutes
 	_ = a.store.SetJSON("general", g)
 	jsonOut(w, 200, g)
 }