feat(shares): close share account directly on withdrawal approval; drop separate closure-request flow

Replaces the auto-submit-closure-request behavior with an immediate
account close, in the same approval action, when a withdrawal brings
shares to zero — matching the backend's new single-step close-on-
approval flow. Removes the now-unneeded Share Closure Request feature
entirely: dedicated create/list components (Clerk Dashboard + Approval
Center), routes, nav links, and the "eligible for closure" banner on
the Share Account view.

Also adds a clear "this will close the account" notice wherever a
withdrawal would zero out the account's shares — the standalone Share
Withdrawal Request page (submit + review) and Transaction Entry's
Share Redemption Transfer confirm dialog — styled as an amber warning
callout rather than a plain info line. Trims that confirm dialog to
just the required details (dropped the redundant ECS A/C No. line and
the validation-checklist block) and compacts its overall size.

src/app/core/shell/shell.component.html

@@ -112,17 +112,6 @@
             </svg>
             My Share Requests
           </a>
-          <a
-            class="cashier-nav__item cashier-nav__item--sec"
-            [class.cashier-nav__item--active]="currentUrl.includes('/clerk/share-closure-request')"
-            [routerLink]="['/clerk/share-closure-requests']"
-          >
-            <svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
-              <rect x="4" y="11" width="16" height="9" rx="2" />
-              <path d="M8 11V7a4 4 0 0 1 8 0v4" />
-            </svg>
-            My Share Closures
-          </a>
           @if (clerkAccountLoaded) {
             <div class="cashier-nav__item-wrap">
               <a