refactor: move libs/shared/src/ui/ into atoms/molecules/organisms (RD-27)

The folder now equals the layer, as CLAUDE.md decision 2 requires. 33
directories move by git mv (25 flat, plus upload/'s 8 subfolders split
across all three layers). 28 distinct @shared/ui/* specifiers rewrite
across 73 files, longest-first. Five relative imports inside upload/
become @shared/ui aliases because their sibling now lives in a
different layer; two stay relative because both ends stay in the same
layer. Four .mdx docs get their seven broken story imports fixed;
atomic-design.mdx's page-shell import is untouched, because layout/
does not move.

No component, template, story title, or layer-tag comment changes.
That is RD-28's job.

Verified against the ticket's acceptance commands: the 26 flat
directories become exactly 3 layer folders with the counts the ticket
names, only three @shared/ui/* prefixes remain (atoms, molecules,
organisms), the .mdx import count holds at 7, and the relative-import
count inside ui/ drops from 7 to 2 as decision 4 requires. The
@shared/ui/ occurrence count moves from 200 to 205: decision 4
mandates turning 5 of those 7 relative imports into @shared/ui/*
aliases, which decision 3's "200 before, 200 after" check does not
account for. The 5-occurrence gap is exactly the 5 conversions decision
4 names, not a lost or duplicated specifier.

npm run ci --full passes: lint, typecheck, dep:check, format, tokens,
seam, both apps' + both libraries' tests, both apps' localized build,
audit, backend tests, all three generated-artifact drift checks, and
both Storybook instances' build + axe-core a11y suite (67+45 suites,
198+112 tests, all green).

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

libs/shared/src/ui/atoms/skeleton/skeleton.component.ts

@@ -0,0 +1,59 @@
+import { Component, OnDestroy, OnInit, computed, input, signal } from '@angular/core';
+
+// CIBG-GAP EXTENSION: Laadindicatie — no vendored loading-skeleton class exists
+// (verified absent from huisstijl.min.css); hand-rolled shimmer, see cibg-gaps.mdx.
+/** Atom: skeleton placeholder (grey shimmer). Delay-gated so it never flashes
+    on fast responses. Render `count` lines shaped roughly like the content. */
+@Component({
+  selector: 'app-skeleton',
+  styles: [
+    `
+      :host {
+        display: block;
+      }
+      .sk {
+        background: linear-gradient(
+          90deg,
+          var(--rhc-color-cool-grey-200) 25%,
+          var(--rhc-color-cool-grey-100) 37%,
+          var(--rhc-color-cool-grey-200) 63%
+        );
+        background-size: 400% 100%;
+        animation: sh 1.4s ease infinite;
+        border-radius: var(--rhc-border-radius-md);
+        margin-block-end: var(--rhc-space-max-lg);
+      }
+      @keyframes sh {
+        0% {
+          background-position: 100% 0;
+        }
+        100% {
+          background-position: 0 0;
+        }
+      }
+    `,
+  ],
+  template: `
+    @if (visible()) {
+      @for (l of lines(); track $index) {
+        <div class="sk" aria-hidden="true" [style.width]="width()" [style.height]="height()"></div>
+      }
+    }
+  `,
+})
+export class SkeletonComponent implements OnInit, OnDestroy {
+  width = input('100%');
+  height = input('1rem');
+  count = input(1);
+  delay = input(150);
+  protected visible = signal(false);
+  protected lines = computed(() => Array(this.count()).fill(0));
+  private timer?: ReturnType<typeof setTimeout>;
+
+  ngOnInit() {
+    this.timer = setTimeout(() => this.visible.set(true), this.delay());
+  }
+  ngOnDestroy() {
+    clearTimeout(this.timer);
+  }
+}