hive-c0re stops owning scheduled prompts; agents lose the schedule tools

Scheduled prompts are swarm-level now (swarmctl schedule, #4936). The hive
keeps the rows it has only so the operator can copy them over.

- hive-c0re no longer fires anything: the scheduled-prompts worker is gone,
  and with it every create/edit/cancel/pause/resume/fire path (dashboard
  endpoints, agent-socket verbs, the SchedulePrompt approval kind and its
  approve handler). The store keeps open + list; GET /api/schedules stays.
- A v6 approvals migration drops schedule_prompt rows.
- Nothing submits approvals any more, so the submit path goes too:
  Approvals::submit_kind (now a test fixture), the ApprovalAdded dashboard
  event and its emitter.
- Coordinator::push_todo, whose only caller was the worker, goes, and with
  it hive_host_sock::agent_todo_socket and hive-c0re's hive-agent-sock /
  hive-sock-client deps.
- The schedules_changed dashboard event goes; nothing mutates the rows.
- Agents lose request_schedule_prompt, cancel_schedule, fire_schedule_now,
  edit_schedule and list_schedules, the `scheduling` tool group, their
  system-prompt line and their transcript formatters. `remind` is unchanged.

hive-c0re/src/actions.rs

@@ -21,7 +21,7 @@ use crate::lifecycle;
 ///
 /// Every queued kind resolves its approval row via
 /// [`resolve_approval_dag`] when the DAG settles terminal.
-pub async fn approve(coord: Arc<Coordinator>, id: i64) -> Result<()> {
+pub fn approve(coord: &Arc<Coordinator>, id: i64) -> Result<()> {
     let approval = coord.approvals.mark_approved(id)?;
     tracing::info!(
         %approval.id,
@@ -50,19 +50,6 @@ pub async fn approve(coord: Arc<Coordinator>, id: i64) -> Result<()> {
             coord.emit_rebuild_queue_snapshot();
             Ok(())
         }
-        ApprovalKind::SchedulePrompt => {
-            // No queue card for SchedulePrompt — the work is a single
-            // sqlite insert, the actual "running" lifetime lives on
-            // the scheduled-prompts surface itself (worker fires it
-            // at the scheduled time). Run inline + fire
-            // `ApprovalResolved` so the approval row leaves Pending
-            // immediately.
-            let result = run_approval_schedule_prompt(&coord, approval).await;
-            if result.is_ok() {
-                coord.emit_schedules_snapshot();
-            }
-            result
-        }
     }
 }
 
@@ -162,37 +149,6 @@ pub(crate) async fn post_rev_deploy_failure_to_pr(agent: &str, rev: &str, err: &
     }
 }
 
-/// Inline (non-queued) handler for `ApprovalKind::SchedulePrompt`.
-/// On approve, decode the `SchedulePromptPayload` JSON from the
-/// approval's `commit_ref`, insert a row into `scheduled_prompts`
-/// (with `source = Approval { id }`), and fire `ApprovalResolved`.
-/// The worker takes over from here — fan-out at fire time.
-async fn run_approval_schedule_prompt(
-    coord: &Coordinator,
-    approval: hive_sh4re::approvals::Approval,
-) -> Result<()> {
-    let result: Result<()> = async {
-        let payload: hive_sh4re::manager::SchedulePromptPayload =
-            serde_json::from_str(&approval.commit_ref)
-                .context("decode SchedulePromptPayload from approval.commit_ref")?;
-        coord
-            .scheduled_prompts
-            .submit(&crate::scheduled_prompts::NewSchedule {
-                owner: approval.agent.to_string(),
-                targets: payload.targets,
-                body: payload.body,
-                first_fire_at_unix: payload.first_fire_at_unix,
-                interval_seconds: payload.interval_seconds,
-                description: payload.description,
-                source: crate::scheduled_prompts::ScheduleSource::Approval { id: approval.id },
-            })
-            .map(|_| ())
-            .context("insert scheduled prompt")
-    }
-    .await;
-    finish_approval(coord, &approval, result)
-}
-
 /// Resolve an approval row from how its DAG's work ended — the body of the
 /// [`NodeKind::ResolveApproval`] tail node. Every approval-carrying template
 /// resolves here: the pipeline is ordinary queue nodes,