feat(WP-67): merge behandelportal into this repo as a monorepo

Restructures into apps/ssp + apps/behandelportal (two Angular projects)
plus libs/shared + libs/beheer (cross-app libraries), replacing WP-61's
separate sibling repo. That split had already produced real drift: a
hand-vendored copy of the backend's OpenAPI doc, a shared/ui+layout tree
forked and silently diverging (7 files), and beheer + the styles.scss
token bridge duplicated byte-for-byte across both repos.

- git mv the SSP's src/app/* into apps/ssp/; fold shared/, beheer/,
  environments/, the Storybook docs/*.mdx, and styles.scss into
  libs/shared + libs/beheer (all confirmed identical between the two
  repos before merging). auth stays deliberately duplicated per
  ADR-0002 (actor-specific, expected to diverge) - amended there.
- One generated API client (libs/shared), no more vendored swagger.json.
- .dependency-cruiser split into a base factory + one config per app,
  and Storybook into .storybook-ssp/.storybook-behandelportal - both
  forced by the @auth/* alias resolving to different directories per app.
- SiteHeaderComponent/ShellComponent gained HEADER_NAV_ITEMS/
  HEADER_ADMIN_LINKS/DEBUG_PANEL injection tokens so each app supplies
  its own nav/admin-links/dev-panel instead of one being hardcoded.
- CLAUDE.md, ARCHITECTURE.md, dependencies.md, and ADR-0002 updated;
  WP-67 backlog entry documents the full decision trail.

npm run ci green (lint, dep:check x2, 360 tests across ssp/
behandelportal/shared/beheer, both localized builds, backend tests,
snippet + api-client drift); both dev servers, both Storybook
instances, and docker compose verified working.

The old sibling repo (/home/eho/repos/behandelportal) is left
untouched, not deleted.

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

apps/ssp/src/app/brief/infrastructure/letter-preview.adapter.ts

@@ -0,0 +1,37 @@
+import { Injectable } from '@angular/core';
+import { Result, ok, err } from '@shared/kernel/fp';
+import { currentRole } from '@shared/infrastructure/role';
+import { problemDetail } from '@shared/infrastructure/api-error';
+import { environment } from '@shared/environments/environment';
+
+const PREVIEW_FAILED = $localize`:@@brief.preview.failed:De voorvertoning kon niet worden geopend.`;
+
+/**
+ * `/brief/preview` returns `text/html`, not JSON, and is `.ExcludeFromDescription()`'d
+ * to keep the NSwag-generated client JSON-only (same seam as uploads) — so this is a
+ * hand-written fetch, not the `ApiClient`. That also means it bypasses `HttpClient`'s
+ * `roleInterceptor`, so `X-Role` is set here explicitly.
+ */
+@Injectable({ providedIn: 'root' })
+export class LetterPreviewAdapter {
+  async preview(): Promise<Result<string, Blob>> {
+    let res: Response;
+    try {
+      res = await fetch(`${environment.apiBaseUrl}/api/v1/brief/preview`, {
+        headers: { 'X-Role': currentRole() },
+      });
+    } catch {
+      return err(PREVIEW_FAILED);
+    }
+    if (!res.ok) return err(await errorMessage(res));
+    return ok(await res.blob());
+  }
+}
+
+async function errorMessage(res: Response): Promise<string> {
+  try {
+    return problemDetail(await res.json(), PREVIEW_FAILED);
+  } catch {
+    return PREVIEW_FAILED;
+  }
+}