feat(shares,tasks): centralized Additional Shares approval queue, remove unused Share Savings Debit

- Add Approval Center tab "Share Addition Requests": lists every pending additional-share tranche
  across all accounts (backed by the new /v1/shareadditionrequests endpoint), with a detail popup
  showing the board resolution and the route-specific proof of funding (voucher(s) for cash, or the
  linked savings account for savings). Approve/Reject call the same native
  approveadditionalshares/rejectadditionalshares commands the account-page buttons already used.
- Remove "Debit from Savings" dialog/button and the "Share Savings Debit" Checker Inbox tab -- zero
  rows ever recorded on either tenant since it was built.
- Remove "Approve Additional Shares"/"Reject Additional Shares" from the account-page menu now that
  every tranche is reviewed from the centralized queue instead.
- Harden SharesButtonsConfiguration.removeButton(): a not-found name fed to splice(-1, 1) was quietly
  deleting the LAST button in the array instead of doing nothing -- removing the two menu entries
  above would otherwise have silently broken the rest of the Active-account button bar.

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

src/app/tasks/checker-inbox-and-tasks/checker-inbox-and-tasks.component.html

@@ -166,12 +166,12 @@
     </a>
     <a
       class="ac-tab"
-      routerLink="./share-savings-debit-requests"
+      routerLink="./share-addition-requests"
       routerLinkActive="ac-tab--active"
       *mifosxHasPermission="'ALL_FUNCTIONS_READ'"
     >
       <fa-icon icon="money-check-alt" class="ac-tab__ic"></fa-icon>
-      <span>Share Savings Debit</span>
+      <span>Share Addition Requests</span>
     </a>
     <a
       class="ac-tab"