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/shares/shares-account-view/shares-account-view.component.html

@@ -124,13 +124,6 @@
   </mat-card-header>
 
   <mat-card-content class="content">
-    @if (sharesAccountData.status?.value === 'Active' && (sharesAccountData.summary?.totalApprovedShares ?? 0) === 0) {
-      <div class="closure-eligible-banner">
-        <fa-icon icon="info-circle"></fa-icon>
-        <span>All shares have been withdrawn from this account — it is now eligible for closure.</span>
-        <a class="closure-eligible-banner__link" [routerLink]="['/clerk/share-closure-request']"> Request Closure </a>
-      </div>
-    }
     <nav mat-tab-nav-bar class="navigation-tabs" [tabPanel]="tabPanel">
       <a
         mat-tab-link