fix(cibg): address fieldset padding + atomic-design audit cleanup

Fix: address-fields shipped a scoped `fieldset { padding:0; margin:0 }` that
tied on specificity with CIBG's `.form-horizontal fieldset` and, injected later,
won — flattening the grey-box padding on "Mijn gegevens" and the registratie
wizard address step. Removed the override (kept the legend rule).

Audit cleanup (minimise atoms, converge or document near-duplicates):
- delete dead `app-card` (+ story; zero consumers, superseded by app-data-block)
  and the unused `.app-info-box` utility
- review-section raw <h2> -> app-heading; registratie-wizard lone <dl> -> app-data-block
- keep application-link's raw <h3> (vendored `.applications li a h3` chain needs
  the bare element) with an inline justification
- document the deliberate "don't merge these" verdicts in a new Convergence
  decisions table in atomic-design.mdx; record the card removal in cibg-gaps.mdx

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/shared/ui/review-section/review-section.component.ts

@@ -1,5 +1,6 @@
 import { Component, input, output } from '@angular/core';
 import { DataBlockComponent } from '@shared/ui/data-block/data-block.component';
+import { HeadingComponent } from '@shared/ui/heading/heading.component';
 
 /** Molecule: one section of a CIBG Huisstijl "controlestap" (wizard review step) —
     a heading with a "Wijzigen" link, and the section's `<app-data-row>`s in a CIBG
@@ -7,10 +8,10 @@ import { DataBlockComponent } from '@shared/ui/data-block/data-block.component';
     heading and decides what "Wijzigen" does (typically jump back to a step). */
 @Component({
   selector: 'app-review-section',
-  imports: [DataBlockComponent],
+  imports: [DataBlockComponent, HeadingComponent],
   template: `
     <div class="d-flex">
-      <h2>{{ heading() }}</h2>
+      <app-heading [level]="2">{{ heading() }}</app-heading>
       @if (showEdit()) {
         <div class="ms-auto">
           <a href="#" [attr.aria-label]="editAriaLabel() || editLabel()" (click)="onEdit($event)">{{