feat(schedules): make schedules pausable

Adds pause/resume support for scheduled prompts.

Backend:
- New paused_at_unix column on scheduled_prompts table (added via
  ALTER TABLE migration so existing databases are upgraded on first
  start). The due-rows index is dropped and recreated to also exclude
  paused rows so the worker never fires them while paused.
- Worker's due() query gains AND paused_at_unix IS NULL filter.
- New pause(id) and resume(id) methods on ScheduledPrompts; both are
  idempotent and refuse cancelled rows.
- New POST /api/schedules/{id}/pause and /api/schedules/{id}/resume
  dashboard endpoints (operator-direct, no approval gate). Both emit
  a schedules snapshot on success so the tab updates live.
- WireSchedule gains paused_at_unix: Option<i64> so the frontend can
  render the state without an extra fetch.

Frontend:
- Paused rows render with a distinct row class + muted opacity.
- The next-fire cell shows a yellow pause glyph + tooltip with the
  paused-since timestamp and the would-have-fired time.
- Actions column: pause/resume toggle button (⏸/▶) beside fire/edit/cancel.
  Fire-now is disabled while paused (resume first).
- Sort order: active → paused → cancelled (paused slot keeps schedules
  visible without mixing them into the active top section).
- pauseSchedule() / resumeSchedule() async functions POST to the new
  endpoints and refresh the table on success.

hive-c0re/src/dashboard.rs

@@ -131,6 +131,14 @@ pub async fn serve(port: u16, coord: Arc<Coordinator>) -> Result<()> {
             "/api/schedules/{id}/cancel",
             post(schedules::post_schedule_cancel),
         )
+        .route(
+            "/api/schedules/{id}/pause",
+            post(schedules::post_schedule_pause),
+        )
+        .route(
+            "/api/schedules/{id}/resume",
+            post(schedules::post_schedule_resume),
+        )
         .route(
             "/api/schedules/{id}/fire-now",
             post(schedules::post_schedule_fire_now),

hive-c0re/src/dashboard/schedules.rs

@@ -228,6 +228,52 @@ pub(super) async fn patch_schedule(
     }
 }
 
+/// `POST /api/schedules/{id}/pause` — pause a schedule so the worker
+/// skips it until explicitly resumed. Idempotent; no-op on an already-
+/// paused row. Returns 404 when the schedule is cancelled or not found.
+pub(super) async fn post_schedule_pause(
+    State(state): State<AppState>,
+    AxumPath(id): AxumPath<i64>,
+) -> Response {
+    match state.coord.scheduled_prompts.pause(id) {
+        Ok(()) => {
+            state.coord.emit_schedules_snapshot();
+            (StatusCode::OK, "ok").into_response()
+        }
+        Err(e) => {
+            let msg = format!("{e:#}");
+            if msg.contains("not found") || msg.contains("cancelled") {
+                (StatusCode::NOT_FOUND, msg).into_response()
+            } else {
+                error_response(&format!("pause schedule {id}: {msg}"))
+            }
+        }
+    }
+}
+
+/// `POST /api/schedules/{id}/resume` — resume a paused schedule.
+/// Idempotent; no-op on an already-active row. Returns 404 when the
+/// schedule is cancelled or not found.
+pub(super) async fn post_schedule_resume(
+    State(state): State<AppState>,
+    AxumPath(id): AxumPath<i64>,
+) -> Response {
+    match state.coord.scheduled_prompts.resume(id) {
+        Ok(()) => {
+            state.coord.emit_schedules_snapshot();
+            (StatusCode::OK, "ok").into_response()
+        }
+        Err(e) => {
+            let msg = format!("{e:#}");
+            if msg.contains("not found") || msg.contains("cancelled") {
+                (StatusCode::NOT_FOUND, msg).into_response()
+            } else {
+                error_response(&format!("resume schedule {id}: {msg}"))
+            }
+        }
+    }
+}
+
 /// `POST /api/schedules/{id}/cancel` — operator-side cancel
 /// (whole schedule when no `targets` field, partial when one is
 /// provided). Operator bypasses the topology check; the manager

hive-c0re/src/scheduled_prompts.rs

@@ -29,11 +29,12 @@ CREATE TABLE IF NOT EXISTS scheduled_prompts (
     created_at_unix   INTEGER NOT NULL,
     source            TEXT    NOT NULL,
     cancelled_at_unix INTEGER,
-    description       TEXT
+    description       TEXT,
+    paused_at_unix    INTEGER
 );
 CREATE INDEX IF NOT EXISTS idx_scheduled_due
     ON scheduled_prompts (next_fire_at_unix)
-    WHERE cancelled_at_unix IS NULL;
+    WHERE cancelled_at_unix IS NULL AND paused_at_unix IS NULL;
 
 CREATE TABLE IF NOT EXISTS scheduled_prompt_targets (
     schedule_id        INTEGER NOT NULL,
@@ -68,6 +69,9 @@ pub struct Schedule {
     /// next pass.
     pub cancelled_at_unix: Option<i64>,
     pub description: Option<String>,
+    /// Set while the schedule is paused. Worker skips rows where
+    /// `paused_at_unix IS NOT NULL`. Cleared by `resume()`.
+    pub paused_at_unix: Option<i64>,
     pub targets: Vec<ScheduleTarget>,
 }
 
@@ -173,6 +177,24 @@ impl ScheduledPrompts {
             .context("enable foreign keys")?;
         conn.execute_batch(SCHEMA)
             .context("apply scheduled_prompts schema")?;
+        // Migration: add paused_at_unix to existing databases.
+        // Silently ignores "duplicate column name" errors so this is
+        // idempotent across daemon restarts on already-migrated DBs.
+        let _ = conn.execute(
+            "ALTER TABLE scheduled_prompts ADD COLUMN paused_at_unix INTEGER",
+            [],
+        );
+        // Migration: recreate the due-rows index to also exclude paused
+        // rows. `CREATE INDEX IF NOT EXISTS` won't update an existing
+        // index's WHERE clause, so we drop + recreate on every open.
+        // The table is small and the op is cheap.
+        conn.execute_batch(
+            "DROP INDEX IF EXISTS idx_scheduled_due;
+             CREATE INDEX idx_scheduled_due
+                 ON scheduled_prompts (next_fire_at_unix)
+                 WHERE cancelled_at_unix IS NULL AND paused_at_unix IS NULL;",
+        )
+        .context("scheduled_prompts: recreate due-index for paused support")?;
         Ok(Self {
             conn: Mutex::new(conn),
         })
@@ -221,7 +243,8 @@ impl ScheduledPrompts {
         let row = conn
             .query_row(
                 "SELECT id, owner, body, interval_seconds, next_fire_at_unix,
-                        created_at_unix, source, cancelled_at_unix, description
+                        created_at_unix, source, cancelled_at_unix, description,
+                        paused_at_unix
                    FROM scheduled_prompts WHERE id = ?1",
                 params![id],
                 row_to_schedule_header,
@@ -242,7 +265,8 @@ impl ScheduledPrompts {
         let conn = self.conn.lock().unwrap();
         let mut stmt = conn.prepare(
             "SELECT id, owner, body, interval_seconds, next_fire_at_unix,
-                    created_at_unix, source, cancelled_at_unix, description
+                    created_at_unix, source, cancelled_at_unix, description,
+                    paused_at_unix
                FROM scheduled_prompts
               ORDER BY next_fire_at_unix ASC, id ASC",
         )?;
@@ -264,9 +288,11 @@ impl ScheduledPrompts {
         let conn = self.conn.lock().unwrap();
         let mut stmt = conn.prepare(
             "SELECT id, owner, body, interval_seconds, next_fire_at_unix,
-                    created_at_unix, source, cancelled_at_unix, description
+                    created_at_unix, source, cancelled_at_unix, description,
+                    paused_at_unix
                FROM scheduled_prompts
-              WHERE cancelled_at_unix IS NULL AND next_fire_at_unix <= ?1
+              WHERE cancelled_at_unix IS NULL AND paused_at_unix IS NULL
+                AND next_fire_at_unix <= ?1
               ORDER BY next_fire_at_unix ASC, id ASC
               LIMIT ?2",
         )?;
@@ -546,6 +572,43 @@ impl ScheduledPrompts {
         Ok(())
     }
 
+    /// Pause a schedule. Idempotent; no-op on an already-paused row.
+    /// The worker skips paused rows so no fires occur while paused;
+    /// `next_fire_at_unix` is preserved so the first resume fires at
+    /// the next intended cadence instant (no catch-up needed — a
+    /// paused schedule simply slips its upcoming fire). Returns
+    /// `Err` when the schedule is cancelled or does not exist.
+    pub fn pause(&self, id: i64) -> Result<()> {
+        let conn = self.conn.lock().unwrap();
+        let now = now_unix();
+        let n = conn.execute(
+            "UPDATE scheduled_prompts
+                SET paused_at_unix = COALESCE(paused_at_unix, ?1)
+              WHERE id = ?2 AND cancelled_at_unix IS NULL",
+            params![now, id],
+        )?;
+        if n == 0 {
+            bail!("schedule {id} not found or is cancelled");
+        }
+        Ok(())
+    }
+
+    /// Resume a paused schedule. Idempotent; no-op on an active row.
+    /// Returns `Err` when the schedule is cancelled or does not exist.
+    pub fn resume(&self, id: i64) -> Result<()> {
+        let conn = self.conn.lock().unwrap();
+        let n = conn.execute(
+            "UPDATE scheduled_prompts
+                SET paused_at_unix = NULL
+              WHERE id = ?1 AND cancelled_at_unix IS NULL",
+            params![id],
+        )?;
+        if n == 0 {
+            bail!("schedule {id} not found or is cancelled");
+        }
+        Ok(())
+    }
+
     /// Reap cancelled rows older than `older_than_unix`. Returns
     /// the number of rows deleted. Called from the worker on each
     /// tick so cancellations clear out of the dashboard without an
@@ -575,6 +638,7 @@ fn row_to_schedule_header(row: &rusqlite::Row) -> rusqlite::Result<Schedule> {
         source: ScheduleSource::from_db_string(&source_str),
         cancelled_at_unix: row.get(7)?,
         description: row.get(8)?,
+        paused_at_unix: row.get(9)?,
         targets: Vec::new(),
     })
 }

hive-c0re/src/socket_server.rs

@@ -2021,6 +2021,7 @@ fn schedule_to_wire(s: crate::scheduled_prompts::Schedule) -> hive_sh4re::WireSc
             }
         },
         cancelled_at_unix: s.cancelled_at_unix,
+        paused_at_unix: s.paused_at_unix,
         description: s.description,
         targets: s
             .targets
@@ -2126,6 +2127,7 @@ mod tests {
             created_at_unix: 0,
             source: hive_sh4re::WireScheduleSource::Operator,
             cancelled_at_unix: None,
+            paused_at_unix: None,
             description: None,
             targets: targets.iter().map(|t| target(t)).collect(),
         }