fix(dashboard): refresh reminders on SCH3DUL3S tab activation + update stale comments

- activateTab('schedules') now calls both refreshSchedules() and
  refreshReminders() since both sections live on the same tab.
  (The previous SYST3M/system target was wrong.)
- Update index.html comment to reflect schedules_changed SSE coverage
- Update index.html reminders comment to mention reminders_changed SSE
- Update tabs.js reminders section comment to reflect SSE coverage

frontend/packages/dashboard/src/index.html

@@ -229,9 +229,10 @@
          toggle for existing schedules. Schedules list driven by
          GET /api/schedules; POST /api/schedules to create, PATCH
          /api/schedules/{id} to edit, POST /api/schedules/{id}/cancel
-         for per-target / whole-row cancel. No SchedulesChanged SSE
-         event yet, so the list re-fetches on tab activation + after
-         each submit / cancel. See docs/web-ui.md::SCH3DUL3S tab. -->
+         for per-target / whole-row cancel. Live updates via
+         `schedules_changed` SSE; tab activation re-fetches as a
+         safety net for disconnect windows.
+         See docs/web-ui.md::SCH3DUL3S tab. -->
     <section class="tab-pane" id="tab-pane-schedules"
              role="tabpanel" aria-labelledby="tab-schedules">
       <h2>◆ SCH3DUL3S ◆</h2>
@@ -245,8 +246,9 @@
            on this tab so the operator has one place for everything
            that fires at a future time — operator-set schedules
            above, agent-self reminders here. Backed by GET
-           /api/reminders; refresh handled by refreshReminders()
-           (called from refreshState). -->
+           /api/reminders; live updates via `reminders_changed` SSE;
+           refreshReminders() called from refreshState + tab
+           activation as safety net for disconnect windows. -->
       <h2>◆ QU3U3D R3M1ND3RS ◆</h2>
       <div class="divider">══════════════════════════════════════════════════════════════</div>
       <p class="meta">reminders agents have queued for themselves but not yet delivered. cancel to drop a stuck or unwanted entry.</p>