Upload feature (e): wire inline upload (registratie beroep) + documenten step (herregistratie)

- Fold UploadState into both wizard machines; route via { tag: 'Upload', msg }
- Gate step validation on requiredCategoriesSatisfied; include deliveryRefs in submit
- Shared createUploadController (effectful glue: categories, transport, focus-poll, File map)
- rejectReason pure format validator + specs; bump registratie storage key to v2

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

src/app/shared/upload/upload.machine.spec.ts

@@ -9,6 +9,7 @@ import {
   requiredCategoriesSatisfied,
   deliveryRefs,
   inFlight,
+  rejectReason,
 } from './upload.machine';
 
 const cat = (over: Partial<DocumentCategory> = {}): DocumentCategory => ({
@@ -217,6 +218,21 @@ describe('deliveryRefs', () => {
   });
 });
 
+describe('rejectReason', () => {
+  it('rejects a disallowed type', () => {
+    expect(rejectReason(cat({ acceptedTypes: ['application/pdf'] }), { type: 'image/png', sizeMb: 1 })).toBe('type');
+  });
+  it('rejects an oversized file', () => {
+    expect(rejectReason(cat({ maxSizeMb: 10 }), { type: 'application/pdf', sizeMb: 11 })).toBe('size');
+  });
+  it('accepts a valid file', () => {
+    expect(rejectReason(cat({ acceptedTypes: ['application/pdf'], maxSizeMb: 10 }), { type: 'application/pdf', sizeMb: 1 })).toBeNull();
+  });
+  it('allows any type when the category lists none', () => {
+    expect(rejectReason(cat({ acceptedTypes: [], maxSizeMb: 10 }), { type: 'image/png', sizeMb: 1 })).toBeNull();
+  });
+});
+
 describe('inFlight', () => {
   it('returns only queued/uploading uploads', () => {
     let s = select(stateWith([cat({ multiple: true })]), 'diploma', 'u1');