add reminder rollup RPC and broker query

Surface reminder activity statistics (scheduled, delivered, pending counts)
for each agent over configurable time windows. Needed by the per-agent
stats page to display reminder metrics.

Adds:
- ReminderStats struct and ReminderRollup request/response variants
- Broker::reminder_rollup_for(agent, since_secs) method
- Agent and manager socket handlers for the new RPC
- SocketReply mapping for response conversion

hive-ag3nt/src/mcp.rs

@@ -48,6 +48,7 @@ pub enum SocketReply {
     Logs(String),
     LooseEnds(Vec<hive_sh4re::LooseEnd>),
     PendingRemindersCount(u64),
+    ReminderRollup(hive_sh4re::ReminderStats),
     Whoami {
         name: String,
         role: String,
@@ -68,6 +69,7 @@ impl From<hive_sh4re::AgentResponse> for SocketReply {
             hive_sh4re::AgentResponse::PendingRemindersCount { count } => {
                 Self::PendingRemindersCount(count)
             }
+            hive_sh4re::AgentResponse::ReminderRollup(stats) => Self::ReminderRollup(stats),
             hive_sh4re::AgentResponse::Whoami {
                 name,
                 role,
@@ -95,6 +97,7 @@ impl From<hive_sh4re::ManagerResponse> for SocketReply {
             hive_sh4re::ManagerResponse::PendingRemindersCount { count } => {
                 Self::PendingRemindersCount(count)
             }
+            hive_sh4re::ManagerResponse::ReminderRollup(stats) => Self::ReminderRollup(stats),
             hive_sh4re::ManagerResponse::Whoami {
                 name,
                 role,

hive-c0re/src/agent_server.rs

@@ -207,6 +207,14 @@ async fn dispatch(req: &AgentRequest, agent: &str, coord: &Arc<Coordinator>) ->
                 },
             }
         }
+        AgentRequest::ReminderRollup { since_secs } => {
+            match coord.broker.reminder_rollup_for(agent, *since_secs) {
+                Ok(stats) => AgentResponse::ReminderRollup(stats),
+                Err(e) => AgentResponse::Err {
+                    message: format!("{e:#}"),
+                },
+            }
+        }
         AgentRequest::Whoami => AgentResponse::Whoami {
             name: agent.to_owned(),
             role: "agent".to_owned(),

hive-c0re/src/broker.rs

@@ -583,6 +583,43 @@ impl Broker {
         Ok(u64::try_from(n).unwrap_or(0))
     }
 
+    /// Reminder rollup stats for an agent over a time window. Returns
+    /// counts of scheduled, delivered, and pending reminders created
+    /// in the last `since_secs` seconds (0 = all reminders).
+    pub fn reminder_rollup_for(&self, agent: &str, since_secs: u64) -> Result<hive_sh4re::ReminderStats> {
+        let conn = self.conn.lock().unwrap();
+        let cutoff_time = if since_secs > 0 {
+            let now = std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .ok()
+                .map(|d| d.as_secs() as i64)
+                .unwrap_or(0);
+            now - since_secs as i64
+        } else {
+            i64::MIN
+        };
+        let scheduled: i64 = conn.query_row(
+            "SELECT COUNT(*) FROM reminders WHERE agent = ?1 AND created_at >= ?2",
+            params![agent, cutoff_time],
+            |row| row.get(0),
+        )?;
+        let delivered: i64 = conn.query_row(
+            "SELECT COUNT(*) FROM reminders WHERE agent = ?1 AND created_at >= ?2 AND sent_at IS NOT NULL",
+            params![agent, cutoff_time],
+            |row| row.get(0),
+        )?;
+        let pending: i64 = conn.query_row(
+            "SELECT COUNT(*) FROM reminders WHERE agent = ?1 AND created_at >= ?2 AND sent_at IS NULL",
+            params![agent, cutoff_time],
+            |row| row.get(0),
+        )?;
+        Ok(hive_sh4re::ReminderStats {
+            scheduled: u64::try_from(scheduled).unwrap_or(0),
+            delivered: u64::try_from(delivered).unwrap_or(0),
+            pending: u64::try_from(pending).unwrap_or(0),
+        })
+    }
+
     /// Delete a reminder by id. Returns the number of rows removed (0
     /// when the id never existed or was already delivered). Hard
     /// delete rather than soft so the row doesn't linger and confuse a

hive-c0re/src/manager_server.rs

@@ -369,6 +369,14 @@ async fn dispatch(req: &ManagerRequest, coord: &Arc<Coordinator>) -> ManagerResp
                 },
             }
         }
+        ManagerRequest::ReminderRollup { since_secs } => {
+            match coord.broker.reminder_rollup_for(MANAGER_AGENT, *since_secs) {
+                Ok(stats) => ManagerResponse::ReminderRollup(stats),
+                Err(e) => ManagerResponse::Err {
+                    message: format!("{e:#}"),
+                },
+            }
+        }
         ManagerRequest::Whoami => ManagerResponse::Whoami {
             name: MANAGER_AGENT.to_owned(),
             role: "manager".to_owned(),

hive-sh4re/src/lib.rs

@@ -110,6 +110,17 @@ pub enum ApprovalStatus {
     Failed,
 }
 
+/// Reminder activity statistics for an agent over a time window.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ReminderStats {
+    /// Total reminders scheduled in the window (created_at >= cutoff).
+    pub scheduled: u64,
+    /// Reminders that have been delivered in the window (sent_at IS NOT NULL).
+    pub delivered: u64,
+    /// Reminders still pending in the window (sent_at IS NULL).
+    pub pending: u64,
+}
+
 impl HostResponse {
     pub fn success() -> Self {
         Self {
@@ -381,6 +392,16 @@ pub enum AgentRequest {
     /// by the harness's per-turn stats sink to snapshot "what was
     /// queued at turn-end time" without paying for a full list.
     CountPendingReminders,
+    /// Reminder statistics for this agent: counts of scheduled, delivered,
+    /// and pending reminders over a time window. Used by the stats page
+    /// to display reminder activity. `since_secs` filters to reminders
+    /// created in the last N seconds (0 = all reminders).
+    ReminderRollup {
+        /// Only count reminders created in the last N seconds from now.
+        /// Pass 0 to include all reminders.
+        #[serde(default)]
+        since_secs: u64,
+    },
     /// Self-introspection: who am I, what role, what rev. All values
     /// derive from coord state (no env access required); useful for
     /// agents to stamp notes / commits / messages with a trustworthy
@@ -445,6 +466,8 @@ pub enum AgentResponse {
     LooseEnds { loose_ends: Vec<LooseEnd> },
     /// `CountPendingReminders` result.
     PendingRemindersCount { count: u64 },
+    /// `ReminderRollup` result: reminder activity stats for the agent.
+    ReminderRollup(ReminderStats),
     /// `Whoami` result: identity + role + the current hyperhive rev
     /// hive-c0re is running against. `role` is `"agent"` for
     /// sub-agents (the only path that reaches this variant of the
@@ -730,6 +753,14 @@ pub enum ManagerRequest {
     /// Count of the manager's own pending reminders. Mirror of
     /// `AgentRequest::CountPendingReminders` on the manager surface.
     CountPendingReminders,
+    /// Reminder statistics: counts of scheduled, delivered, and pending
+    /// reminders (manager-flavour). Mirror of `AgentRequest::ReminderRollup`.
+    ReminderRollup {
+        /// Only count reminders created in the last N seconds from now.
+        /// Pass 0 to include all reminders.
+        #[serde(default)]
+        since_secs: u64,
+    },
     /// Manager-flavour self-introspection. Same wire shape as
     /// `AgentRequest::Whoami`, but `role` is always `"manager"`.
     Whoami,
@@ -788,6 +819,8 @@ pub enum ManagerResponse {
     PendingRemindersCount {
         count: u64,
     },
+    /// `ReminderRollup` result: reminder activity stats for the manager.
+    ReminderRollup(ReminderStats),
     /// `Whoami` result: manager identity. `role` is always
     /// `"manager"`. Mirror of `AgentResponse::Whoami`.
     Whoami {