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/shared/application/access.store.ts

@@ -33,4 +33,11 @@ export class AccessStore {
     const rd = this.capabilities();
     return rd.tag === 'Success' && rd.value.includes(capability);
   }
+
+  /** True once `/me` has resolved (success or failure) — lets a page-level gate tell
+      "still loading" apart from "denied", so an admin doesn't flash the denial alert. */
+  readonly ready = computed(() => {
+    const tag = this.capabilities().tag;
+    return tag === 'Success' || tag === 'Failure';
+  });
 }

src/app/shared/upload/upload.adapter.ts

@@ -38,6 +38,12 @@ export interface XhrUploadHandle {
 /** Sentinel rejection so the caller can tell a user-cancel from a real failure. */
 export const UPLOAD_ABORTED = Symbol('upload-aborted');
 
+/** Direct URL to a stored document's bytes. Pure (no injection) so a store can build
+    a letterhead-logo `src` without pulling `ApiClient` into its dependency graph. */
+export function uploadContentUrl(documentId: string): string {
+  return `${environment.apiBaseUrl}/api/v1/uploads/${documentId}/content`;
+}
+
 /**
  * Infrastructure: the only place upload HTTP lives. Reads (categories, status,
  * delete) go through the NSwag client; the multipart POST is hand-written XHR
@@ -94,7 +100,7 @@ export class UploadAdapter {
    * browser opens it. demo-* ids (dev simulation) have no bytes and 404 here.
    */
   contentUrl(documentId: string): string {
-    return `${environment.apiBaseUrl}/api/v1/uploads/${documentId}/content`;
+    return uploadContentUrl(documentId);
   }
 
   /**