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-core-agent-sock/src/lib.rs

@@ -9,8 +9,6 @@
 
 use hive_sh4re::container::MatrixIdentity;
 use hive_sh4re::inbox::{CancelLooseEndKind, DeliveredMessage, InboxRow, LooseEnd};
-use hive_sh4re::manager::SchedulePromptPayload;
-use hive_sh4re::schedule::WireSchedule;
 use hive_types::Ident;
 use serde::{Deserialize, Serialize};
 
@@ -20,8 +18,7 @@ fn default_true() -> bool {
 }
 
 /// Unified request enum for both agent and manager sockets. The agent's
-/// identity is the socket it arrived on. Privileged variants are marked
-/// `*(privileged)*` — an agent socket returns `Err` for them server-side.
+/// identity is the socket it arrived on.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "cmd", rename_all = "snake_case")]
 pub enum Request {
@@ -111,40 +108,9 @@ pub enum Request {
     /// DAG's drain node resolve immediately instead of waiting out its
     /// timeout fallback — same shape as `GracefulStopComplete`.
     PauseAcknowledged,
-
-    // ---- privileged (manager socket only for now) ---------------------------
-    /// *(privileged)* Queue an approval to add a scheduled prompt.
-    RequestSchedulePrompt(SchedulePromptPayload),
-    /// *(privileged)* Cancel a scheduled prompt.
-    CancelSchedule {
-        id: i64,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        targets: Option<Vec<String>>,
-    },
-    /// List every schedule in the hive, whoever owns it.
-    ListSchedules,
-    /// *(privileged)* Fire a scheduled prompt out of band immediately.
-    FireScheduleNow { id: i64 },
-    /// *(privileged)* Edit an existing schedule's mutable fields.
-    EditSchedule {
-        id: i64,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        body: Option<String>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        description: Option<Option<String>>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        interval_seconds: Option<Option<u64>>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        next_fire_at_unix: Option<i64>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        targets_add: Option<Vec<String>>,
-        #[serde(default, skip_serializing_if = "Option::is_none")]
-        targets_remove: Option<Vec<String>>,
-    },
 }
 
-/// Unified response enum for both agent and manager sockets. Privileged
-/// variants (`Schedules`) are never returned on agent sockets.
+/// Unified response enum for both agent and manager sockets.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(tag = "kind", rename_all = "snake_case")]
 pub enum Response {
@@ -211,10 +177,6 @@ pub enum Response {
         #[serde(default, skip_serializing_if = "Vec::is_empty")]
         matrix_accounts: Vec<MatrixIdentity>,
     },
-    /// `ListSchedules` result. Snapshot of the schedules the requester is
-    /// authorized to see — see `ListSchedules`'s own doc comment.
-    /// Returned on the manager socket only.
-    Schedules { schedules: Vec<WireSchedule> },
     /// `Recv` result when a graceful stop is pending for this agent
     /// (set by hive-c0re's `GracefulStop` orchestration). Returned in
     /// place of `Messages` — it doubles as the inbound fence: the harness