feat(fp): WP-26 — admin org-template editor

Edit the letter's org identity in place on the same canvas the drafter composes
on (editableRegions='template'): letterhead/signature/footer become inline
controls, content a read-only sample. Margins (bounded), logo upload (reuses the
shared upload transport + single-upload), version history + rollback, proefbrief,
and publish-with-impact-confirmation. House form-machine idiom
(org-template.machine.ts) + root store with debounced save. Capability-gated
(orgtemplate:edit) with a deny-by-default alert; route /brief/huisstijl.

Backend + generated client were already in place (WP-23). Also fixes a
pre-existing red check:tokens (WP-24 canvas hex fallbacks) and threads the
published logo through to the drafter's canvas.

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

src/app/app.routes.ts

@@ -51,6 +51,12 @@ export const routes: Routes = [
         canActivate: [authGuard],
         loadComponent: () => import('@brief/ui/brief.page').then((m) => m.BriefPage),
       },
+      {
+        path: 'brief/huisstijl',
+        canActivate: [authGuard],
+        loadComponent: () =>
+          import('@brief/ui/org-template.page').then((m) => m.OrgTemplatePage),
+      },
       {
         path: 'concepts',
         loadComponent: () => import('./showcase/concepts.page').then((m) => m.ConceptsPage),