T7.4 - A2: one warning, said once, visible from anywhere

The same not-release-ready warning rendered three times on the creator:
1. the release banner under the context bar   - STAYS, and is now the only one
2. updateStickyStatus() in the sticky save bar - removed
3. a static field-hint under the status radios - removed

The count moved to a badge on the Constraints rail entry (D3's rail replaced
the tabs A2's "tab count badge" referred to). The rail is position:sticky at
BOTH widths, so the badge is on screen from any section at 390px and 1440px -
measured with the constraint table AND the banner both scrolled out of view.
The badge is a number, not a colour: the count is the content, and the rail
entry carries an aria-label saying it ("Constraints - 3 open").

The banner is now role="status" (the login.html aria-live pattern, per C1) and
only rewrites when its message actually changes - a live region that repaints
on every save announces on every save.

Duplicate 2 was not just noise. It wrote the warning with textContent into
the SAME span the B5 autosave indicator mounts into, destroying the indicator
on every count change. Removing the duplicate is what fixes that; the probe
pins the indicator's survival across banner updates.

Verification (each probe run alone): NEW tests/warning_check.py 17/17.
Regressions: hold_check 50/50, form_structure_check 50/51 (the standing F6
height gap, re-measured after T7.5 as recorded at T7.2).

Items: A2

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

html/wp-creation-styles.css

@@ -762,6 +762,12 @@
   .sec-rail-item:hover { color: var(--accent); border-color: var(--border); }
   /* Not colour alone: the current entry is bolder, keeps a left marker and is the
      one carrying aria-current. */
+  /* A2: the open-constraint count. Red chip + a number - the number is the
+     content, so the state is never colour-only. Sized to stay legible at 390px. */
+  .sec-badge { display:inline-block; margin-left:8px; min-width:18px; padding:1px 6px;
+    border-radius:9px; background:var(--red); color:var(--cds-text-on-color);
+    font-size:12px; font-weight:700; line-height:16px; text-align:center; }
+  .sec-badge[hidden] { display:none; }
   .sec-rail-item.is-current {
     color: var(--accent); font-weight: 700;
     background: var(--accent-dim);
@@ -1017,9 +1023,6 @@
     border-top:1px solid var(--border-strong); box-shadow:var(--wp-shadow-sticky); }
   .sticky-save .sticky-status{ font-size:13px; font-weight:600; }
   .sticky-save .sticky-actions{ display:flex; gap:10px; }
-  .ss-ready{ color:var(--accent-green); }
-  .ss-notready{ color:var(--accent-amber); }
-  .ss-hold{ color:var(--red); }
   body.has-sticky-save .main{ padding-bottom:74px; }
 
   /* Disciplines + per-discipline scope */