fix(dashboard): useMergeAdvanceNotice tests should waitFor toBeDefined

`notice` is `events.find(...)` which returns `undefined` (not `null`)
when no match. `waitFor(() => expect(...).not.toBeNull())` exited
immediately because `undefined !== null` — the test never actually
waited for the api mock to resolve. Sometimes the followup assertions
happened to land after the events fetched (test passed by luck);
sometimes they ran while notice was still undefined and the assertions
failed.

Switched all five waitFor sites to `.toBeDefined()` so they actually
block on the events-fetch resolution.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/dashboard/app/components/ScriptsModal.css

@@ -1951,6 +1951,44 @@
   letter-spacing: 0.5px;
   color: var(--text-muted);
   margin-bottom: var(--space-sm);
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: var(--space-sm);
+  flex-wrap: wrap;
+}
+
+.gm-status-advances-help {
+  margin: var(--space-sm) 0;
+  padding: var(--space-sm) var(--space-md);
+  background: color-mix(in srgb, var(--accent, #4a8af4) 6%, transparent);
+  border-left: 3px solid var(--accent, #4a8af4);
+  border-radius: var(--radius-sm);
+  font-size: 12px;
+  text-transform: none;
+  letter-spacing: normal;
+  color: var(--text);
+  font-weight: normal;
+}
+
+.gm-status-advances-help p {
+  margin: 0 0 var(--space-sm) 0;
+}
+
+.gm-status-advances-help p:last-child {
+  margin-bottom: 0;
+}
+
+.gm-status-advances-help-list {
+  list-style: disc;
+  margin: 0 0 var(--space-sm) 0;
+  padding-left: var(--space-lg);
+  display: block;
+}
+
+.gm-status-advances-help-list li {
+  padding: 2px 0;
+  background: none;
 }
 
 .gm-status-advances ul {