fix(chequebook,ctsclearing): surface global stock allocation in UI; fix decided-state check

Receive Stock form now displays the actual highest-allocated serial across
every series (not just silently prefilling the field), so the operator
can see and trust the auto-suggested range start rather than taking it
on faith.

Fixes a real bug where item.decision (which InwardClearingItem.java always
sets to the literal string "PENDING" at creation, never null) was checked
with a plain truthy test everywhere a "has this been decided yet" branch
was needed. Since "PENDING" is a non-empty string, that check was always
true — silently breaking the Decide/View button label, the collapsed
validation summary, the "Awaiting settlement" text, and the decision
dialog itself (which never showed the actual Pass/Return form, even for
still-pending items). Replaced with a proper isDecided() check everywhere.

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

src/app/ctsclearing/inward-batch-detail/item-decision-dialog/item-decision-dialog.component.html

@@ -283,7 +283,7 @@
     }
   }
 
-  @if (item.decision) {
+  @if (isDecided) {
     <h3 class="section-title">Decision</h3>
     <div class="decided-summary" [ngClass]="pillClass(item.decision)">
       <div class="decided-headline">
@@ -372,9 +372,9 @@
 
 <div mat-dialog-actions align="end">
   <button mat-raised-button type="button" mat-dialog-close>
-    {{ (item.decision ? 'labels.buttons.Close' : 'labels.buttons.Cancel') | translate }}
+    {{ (isDecided ? 'labels.buttons.Close' : 'labels.buttons.Cancel') | translate }}
   </button>
-  @if (!item.decision) {
+  @if (!isDecided) {
     <button
       mat-raised-button
       [color]="mode === 'RETURN' ? 'warn' : 'primary'"