integrate reminder stats into stats page via socket RPC

Add fetch_reminder_stats() helper to query ReminderRollup from broker,
and update api_stats endpoint to include reminder stats in snapshot.
Reminder activity metrics (scheduled, delivered, pending) are now
available to the stats page UI for display.

hive-ag3nt/src/web_ui.rs

@@ -221,11 +221,20 @@ struct StatsQuery {
 }
 
 async fn api_stats(
-    State(_state): State<AppState>,
+    State(state): State<AppState>,
     axum::extract::Query(q): axum::extract::Query<StatsQuery>,
 ) -> axum::Json<crate::stats::Snapshot> {
     let window = crate::stats::Window::parse(q.window.as_deref().unwrap_or("24h"));
-    axum::Json(crate::stats::snapshot_default(window))
+    let mut snapshot = crate::stats::snapshot_default(window);
+    // Fetch reminder stats from the broker. The window spans are:
+    // 24h = 86400s, 7d = 604800s, 30d = 2592000s.
+    let window_secs = match window {
+        crate::stats::Window::Day => 24 * 3600,
+        crate::stats::Window::Week => 7 * 24 * 3600,
+        crate::stats::Window::Month => 30 * 24 * 3600,
+    };
+    snapshot.reminder_stats = fetch_reminder_stats(&state.socket, state.flavor(), window_secs as u64).await;
+    axum::Json(snapshot)
 }
 
 #[derive(Serialize)]
@@ -392,6 +401,40 @@ async fn recent_inbox(socket: &std::path::Path, flavor: Flavor) -> Vec<hive_sh4r
     }
 }
 
+/// Fetch reminder activity stats from the broker via the per-agent /
+/// manager socket. Returns None on any transport / decode failure — the
+/// stats are decorative, not authoritative.
+async fn fetch_reminder_stats(socket: &std::path::Path, flavor: Flavor, window_secs: u64) -> Option<hive_sh4re::ReminderStats> {
+    match flavor {
+        Flavor::Agent => {
+            match client::request::<_, hive_sh4re::AgentResponse>(
+                socket,
+                &hive_sh4re::AgentRequest::ReminderRollup {
+                    since_secs: window_secs,
+                },
+            )
+            .await
+            {
+                Ok(hive_sh4re::AgentResponse::ReminderRollup(stats)) => Some(stats),
+                _ => None,
+            }
+        }
+        Flavor::Manager => {
+            match client::request::<_, hive_sh4re::ManagerResponse>(
+                socket,
+                &hive_sh4re::ManagerRequest::ReminderRollup {
+                    since_secs: window_secs,
+                },
+            )
+            .await
+            {
+                Ok(hive_sh4re::ManagerResponse::ReminderRollup(stats)) => Some(stats),
+                _ => None,
+            }
+        }
+    }
+}
+
 // ---------------------------------------------------------------------------
 // Action handlers
 // ---------------------------------------------------------------------------