dashboard: SCH3DUL3S is a read-only list with a removal banner

The tab lists the rows left in the hive's store so the operator can
recreate them with `swarmctl schedule add`: no create row, edit form,
fire/pause/cancel buttons or schedules_changed subscription. The next
column shows the stored next fire time as an absolute UTC timestamp (the
value for --at) instead of a countdown. A warning banner says the page is
slated for removal and points at swarmctl. The approvals view drops the
schedule_prompt card and the approval_added subscription.

frontend/packages/dashboard/src/tabs.js

@@ -17,7 +17,7 @@ import { el } from "@hive/shared/dom.js";
 import { bindAsyncForms } from "@hive/shared/forms.js";
 import { createTabStrip } from "@hive/shared/tabs.js";
 import { containersState, syncContainersFromSnapshot } from "./state.js";
-import { fmtAgo, fmtDuration } from "./util.js";
+import { fmtAgo } from "./util.js";
 import {
   applyCapabilitiesChanged,
   applyToolGroupsChanged,
@@ -25,18 +25,13 @@ import {
   fetchAndRenderToolGroups,
   initPermissions,
 } from "./permissions.js";
-import {
-  applySchedulesChanged,
-  refreshSchedules,
-  activeScheduleCount,
-} from "./schedules.js";
+import { refreshSchedules, activeScheduleCount } from "./schedules.js";
 import {
   initCall,
   refreshOperatorInbox,
   operatorInboxAppendFromEvent,
   operatorInboxCount,
   syncApprovalsFromSnapshot,
-  applyApprovalAdded,
   applyApprovalResolved,
   renderApprovals,
   activeApprovalCount,
@@ -95,11 +90,9 @@ window.marked = marked;
   // opts out via `data-no-refresh` (its mutation arrives via an SSE event).
   bindAsyncForms(() => refreshState());
 
-  // One ticker feeds two live displays that would otherwise only
-  // update on the next SSE-triggered re-render: approval request-age
-  // chips (`.approval-ts`, flips `.stale` at the 1h mark) and schedule
-  // next-fire countdowns (`.sched-due`, stamped with `data-due-at` by
-  // the renderers so this loop can refresh them without a full re-render).
+  // Refreshes approval request-age chips (`.approval-ts`, flips `.stale`
+  // at the 1h mark), which would otherwise only update on the next
+  // SSE-triggered re-render.
   setInterval(() => {
     const now = Math.floor(Date.now() / 1000);
     document
@@ -111,13 +104,6 @@ window.marked = marked;
         node.textContent = "requested " + fmtAgo(requestedAt);
         node.classList.toggle("stale", ageSec >= 3600);
       });
-    document.querySelectorAll(".sched-due[data-due-at]").forEach((node) => {
-      const dueAt = Number(node.getAttribute("data-due-at"));
-      if (!Number.isFinite(dueAt)) return;
-      const dueIn = dueAt - now;
-      node.textContent =
-        dueIn <= 0 ? "overdue " + fmtAgo(dueAt) : fmtDuration(dueIn);
-    });
   }, 1000);
 
   // ─── state polling ──────────────────────────────────────────────────────
@@ -284,7 +270,6 @@ window.marked = marked;
   // and filter client-side — the dashboard ignores broker traffic
   // and the inbox ignores mutation events.
   const MUTATION_HANDLERS = {
-    approval_added: applyApprovalAdded,
     approval_resolved: applyApprovalResolved,
     transient_set: applyTransientSet,
     transient_cleared: applyTransientCleared,
@@ -295,7 +280,6 @@ window.marked = marked;
     // /builds.html gives it for its JobqGraph mount handle's .refresh()
     // (its own separate subscription).
     rebuild_queue_changed: applyRebuildQueueChanged,
-    schedules_changed: applySchedulesChanged,
     capabilities_changed: applyCapabilitiesChanged,
     tool_groups_changed: applyToolGroupsChanged,
   };
@@ -309,15 +293,15 @@ window.marked = marked;
     //
     // kinds= matches MUTATION_HANDLERS below verbatim, plus `sent`
     // (checked separately, just above, for the operator inbox) —
-    // narrows this from all 15 wire kinds down to the 11 this page
+    // narrows this from all 13 wire kinds down to the 9 this page
     // actually acts on. This page was one of 4 unfiltered
     // `/api/dashboard/stream` subscribers before this (subscription
     // discipline, part 1 of the dashboard-event-stream-split issue).
     const es = openStream(
-      "/api/dashboard/stream?kinds=sent,approval_added,approval_resolved," +
+      "/api/dashboard/stream?kinds=sent,approval_resolved," +
         "transient_set,transient_cleared," +
         "container_state_changed,container_removed,rebuild_queue_changed," +
-        "schedules_changed,capabilities_changed,tool_groups_changed",
+        "capabilities_changed,tool_groups_changed",
     );
     es.onmessage = (e) => {
       let ev;
@@ -436,8 +420,7 @@ window.marked = marked;
     const rawTitle = document.title.replace(/^\(\d+\) /, "");
     document.title = callCount > 0 ? `(${callCount}) ${rawTitle}` : rawTitle;
     // SCH3DUL3S — count of schedules with at least one still-active
-    // target (whole-schedule cancellation or all-targets-cancelled
-    // means "not waiting on the worker"; those don't pull attention).
+    // target: the ones left to recreate with `swarmctl schedule`.
     setTabCount("schedules", activeScheduleCount());
   }
   // Poll the state stores on a 1s tick to keep the pill counts in