fix: use try_from for i64/u64 casts; split format_notification into helpers

hive-ag3nt/src/web_ui.rs

@@ -335,8 +335,7 @@ async fn api_stats(
     // Pass the window span to the reminder-stats RPC so the broker
     // filters its counts to the same time range as the chart data.
     let window_secs = window.span_secs();
-    #[allow(clippy::cast_sign_loss)] // window span is always a positive duration
-    let window_secs_u = window_secs.max(0) as u64;
+    let window_secs_u = u64::try_from(window_secs).unwrap_or(0);
     snapshot.reminder_stats = fetch_reminder_stats(&state.socket, state.flavor(), window_secs_u).await;
     axum::Json(snapshot)
 }