fix(#2650,#2649): drop reminders tab + pending_reminders chip

hive-c0re's broker reminder store and /api/reminders endpoint were
removed in PR #2644 (reminders migrated to in-container sqlite store).
The dashboard had a QU3U3D R3M1ND3RS section on the schedules tab backed
by that endpoint, and a per-agent badge driven by pending_reminders
(always 0 after the migration).

Remove both. Per-agent reminders now surface through get_loose_ends /
the todos pill on the agent page, consistent with the todos migration.

- frontend/packages/dashboard/src/schedules.js: drop refreshReminders,
  renderReminders, applyRemindersChanged; drop appendLinkified import
  (no longer used); update module comment.
- frontend/packages/dashboard/src/tabs.js: drop applyRemindersChanged
  and refreshReminders imports; remove reminders-section from managed
  list; remove refreshReminders call site; drop reminders_changed from
  SSE dispatch; simplify countdown ticker (reminder-due gone).
- frontend/packages/dashboard/src/dashboard.html: remove QU3U3D
  R3M1ND3RS section.
- frontend/packages/dashboard/src/dashboard.css: remove reminder list +
  row CSS.
- frontend/packages/dashboard/src/common.css: remove .badge-reminder.
- frontend/packages/dashboard/src/swarm.js: remove pending_reminders
  from fingerprint key and badge render.

frontend/packages/dashboard/src/tabs.js

@@ -28,8 +28,8 @@ import {
   initPermissions,
 } from './permissions.js';
 import {
-  applySchedulesChanged, applyRemindersChanged,
-  refreshSchedules, refreshReminders, activeScheduleCount,
+  applySchedulesChanged,
+  refreshSchedules, activeScheduleCount,
 } from './schedules.js';
 import {
   initCall,
@@ -105,11 +105,10 @@ window.marked = marked;
   // a request pending for an hour could still show "0s ago" without
   // this ticker. Also flips `.stale` (amber highlight) at exactly 1h
   // rather than only at the next re-render.
-  // Live countdown for reminder due-at labels and schedule next-fire
-  // cells. Both renderers stamp `data-due-at` on the element so this
-  // single ticker keeps them fresh without triggering a full re-render.
-  // `.reminder-due` -> "overdue X ago" / "in Y"
-  // `.sched-due`    -> same pattern
+  // Live countdown for schedule next-fire cells. Renderers stamp
+  // `data-due-at` on `.sched-due` elements so this single ticker keeps
+  // them fresh without triggering a full re-render. Also keeps
+  // `.approval-ts` stale-highlight fresh at the 1h boundary.
   setInterval(() => {
     const now = Math.floor(Date.now() / 1000);
     document.querySelectorAll('.approval-ts[data-requested-at]').forEach((node) => {
@@ -119,13 +118,13 @@ window.marked = marked;
       node.textContent = 'requested ' + fmtAgo(requestedAt);
       node.classList.toggle('stale', ageSec >= 3600);
     });
-    document.querySelectorAll('.reminder-due[data-due-at], .sched-due[data-due-at]').forEach((node) => {
+    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)
-        : (node.classList.contains('reminder-due') ? 'in ' : '') + fmtDuration(dueIn);
+        : fmtDuration(dueIn);
     });
   }, 1000);
 
@@ -139,7 +138,6 @@ window.marked = marked;
     'questions-section',
     'inbox-section',
     'approvals-section',
-    'reminders-section',
     'schedules-section',
     'capabilities-section',
     'tool-groups-section',
@@ -248,7 +246,6 @@ window.marked = marked;
       // #inbox-section element to render into.)
       syncApprovalsFromSnapshot(s);
       renderApprovals();
-      refreshReminders();
       refreshSchedules();
       restoreOpenDetails(openDetails);
       notifyDeltas(s);
@@ -310,7 +307,6 @@ window.marked = marked;
     // rebuild_queue_changed stays: it refreshes the SW4RM badges.
     rebuild_queue_changed:   applyRebuildQueueChanged,
     schedules_changed:       applySchedulesChanged,
-    reminders_changed:       applyRemindersChanged,
     capabilities_changed:    applyCapabilitiesChanged,
     tool_groups_changed:     applyToolGroupsChanged,
   };
@@ -370,8 +366,8 @@ window.marked = marked;
     renderSelectionBar(Array.from(containersState.values()));
     // Re-fetch on activation as a safety net: SSE covers live mutations,
     // re-sync covers disconnect windows / approval-path inserts that
-    // don't yet emit. SCH3DUL3S also re-fetches reminders (same tab).
-    if (target === 'schedules') { refreshSchedules(); refreshReminders(); }
+    // don't yet emit.
+    if (target === 'schedules') { refreshSchedules(); }
     // Permissions tables: SSE covers worker-applied changes
     // (capabilities_changed / tool_groups_changed); re-fetch on
     // activation as a safety net for any gap between SSE events and