feat(clients): maker-checker for client edits (frontend)

- New "Pending Client Edits" screen under Checker Inbox & Tasks: server-driven pagination,
  date range + Today/Yesterday/All presets, status filter (Pending/Approved/Rejected), search —
  mirrors ChequebookRequestsComponent's architecture.
- Compare dialog diffs the maker's proposed values against a point-in-time "before" snapshot
  (client-edit-diff.util.ts) captured when the edit page was opened, so only genuinely changed
  fields show — works correctly for Pending, Approved, and Rejected edits alike, since it no
  longer depends on comparing against the live (possibly already-updated) client record.
- edit-client.component.ts: General tab save now submits for approval instead of applying
  immediately, shows a pending-approval banner, and blocks a second submission while one's
  outstanding.
- error-handler.interceptor.ts: added the new /clients/{id}/edit/pending check to the existing
  "expected 403/404, don't alert" allowlist (same pattern already used for client images/KYC).

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

src/app/clients/edit-client/edit-client.component.html

@@ -25,9 +25,22 @@
         {{ 'labels.inputs.GENERAL' | translate }}
       </ng-template>
       <div class="tab-content" [class.tab-content--readonly]="isTabReadOnly(0)">
+        @if (hasPendingGeneralEdit) {
+          <div class="pending-edit-banner">
+            <mat-icon>hourglass_top</mat-icon>
+            <span
+              >An edit is awaiting approval from another user. You can't submit another edit until it's resolved.</span
+            >
+          </div>
+        }
         <div class="tab-mode-bar">
           @if (isTabReadOnly(0)) {
-            <button mat-flat-button class="tab-mode-btn tab-mode-btn--edit" (click)="enableTabEdit(0)">
+            <button
+              mat-flat-button
+              class="tab-mode-btn tab-mode-btn--edit"
+              [disabled]="hasPendingGeneralEdit"
+              (click)="enableTabEdit(0)"
+            >
               <mat-icon>edit</mat-icon> Edit
             </button>
           } @else {