tabs.js: drop scheduled-prompts cookies (#712 batch 9)

#459 (dashboard tab + creation form for scheduled prompts —
closed) ×2 (section header + tab-activation re-fetch comment) +
#444 (make it possible to schedule prompts — closed) ×1 (Backend
endpoint enumeration preamble) + #535 (schedules-as-table —
closed) ×1 (renderSchedulesList layout rationale). The
section-header comment now reads as a pure mile-marker; the
backend-endpoints preamble enumerates what the API surface is
today; the table-layout comment describes the rendered shape.
No docs/web-ui.md matches for any of #444 / #459 / #535.

frontend/packages/dashboard/src/tabs.js

@@ -2093,8 +2093,8 @@ window.marked = marked;
     return Math.floor(secs / 86400) + 'd ' + Math.floor((secs % 86400) / 3600) + 'h';
   }
 
-  // ─── scheduled prompts (#459) ──────────────────────────────────────────
-  // Backend (#444) exposes `/api/schedules` (snapshot), `/api/schedules`
+  // ─── scheduled prompts ─────────────────────────────────────────────────
+  // Backend exposes `/api/schedules` (snapshot), `/api/schedules`
   // (POST, operator-direct submit), `/api/schedules/{id}/cancel`
   // (whole or per-target). No SSE channel for schedule mutations yet,
   // so we refresh on tab activation + after every submit/cancel POST.
@@ -2353,7 +2353,7 @@ window.marked = marked;
     return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(date.getDate())}`
       + `T${pad(date.getHours())}:${pad(date.getMinutes())}`;
   }
-  // #535: schedules render as a single table — one row per schedule,
+  // Schedules render as a single table — one row per schedule,
   // attribute columns + one ✓/✕ column per agent (tilted 45° header
   // so a row of agents takes ~28px each instead of full word width),
   // actions column on the right. Edit form expands into a colspan'd
@@ -3254,8 +3254,8 @@ window.marked = marked;
     // on hashchange without waiting for the next SSE update.
     document.body.dataset.activeTab = target;
     renderSelectionBar(Array.from(containersState.values()));
-    // #459: schedules pane has no SSE channel yet (PR C follow-up), so
-    // re-fetch on activation so the operator never lands on stale data.
+    // Schedules pane has no SSE channel for mutations, so re-fetch
+    // on activation so the operator never lands on stale data.
     if (target === 'schedules') refreshSchedules();
   }
   function syncTabFromHash() {