feat(behandelportal): WP-65b beoordeling besluit (decision write)

Adds POST /beoordeling/{id}/besluit: a Besluit enum (Goedkeuren/Afwijzen/
MeerInfoOpvragen) backed by new Aanvraag.BesluitStatus/BesluitToelichting
columns, gated by the same BeoordelingRules.CanDecide the read side's
canBesluiten flag already uses (409 on an illegal transition, 400 on a
missing required toelichting). Mappers.ToStatusDto gains the "a recorded
decision wins" branch. FE: besluit.machine.ts + besluit-form organism
(same form idiom as change-request-form), wired into the beoordeling page
behind the server's canBesluiten flag.

Completes WP-65 (65a + 65b) — verified end-to-end against a running
backend (werkvoorraad -> beoordeling -> besluit -> status reflected back).

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

apps/behandelportal/src/app/behandeling/domain/besluit.machine.spec.ts

@@ -0,0 +1,68 @@
+import { describe, it, expect } from 'vitest';
+import { BesluitState, reduce, initial } from './besluit.machine';
+
+const editingWith = (besluit: string, toelichting = ''): BesluitState => ({
+  tag: 'Editing',
+  draft: { besluit, toelichting },
+  errors: {},
+});
+
+describe('besluit reduce', () => {
+  it('SetField updates the draft while editing', () => {
+    const s = reduce(initial, { tag: 'SetField', key: 'besluit', value: 'Goedkeuren' });
+    expect(s.tag).toBe('Editing');
+    expect((s as Extract<BesluitState, { tag: 'Editing' }>).draft.besluit).toBe('Goedkeuren');
+  });
+
+  it('Submit with no besluit chosen stays Editing and reports a field error', () => {
+    const s = reduce(editingWith(''), { tag: 'Submit' });
+    expect(s.tag).toBe('Editing');
+    expect((s as Extract<BesluitState, { tag: 'Editing' }>).errors.besluit).toBeTruthy();
+  });
+
+  it('Submit Afwijzen without a toelichting stays Editing and reports a field error', () => {
+    const s = reduce(editingWith('Afwijzen'), { tag: 'Submit' });
+    expect(s.tag).toBe('Editing');
+    expect((s as Extract<BesluitState, { tag: 'Editing' }>).errors.toelichting).toBeTruthy();
+  });
+
+  it('Submit Goedkeuren with no toelichting moves to Submitting (optional there)', () => {
+    const s = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    expect(s.tag).toBe('Submitting');
+    expect((s as Extract<BesluitState, { tag: 'Submitting' }>).data).toEqual({
+      besluit: 'Goedkeuren',
+      toelichting: undefined,
+    });
+  });
+
+  it('Submit Afwijzen with a toelichting moves to Submitting with the trimmed value', () => {
+    const s = reduce(editingWith('Afwijzen', '  niet erkend  '), { tag: 'Submit' });
+    expect(s.tag).toBe('Submitting');
+    expect((s as Extract<BesluitState, { tag: 'Submitting' }>).data).toEqual({
+      besluit: 'Afwijzen',
+      toelichting: 'niet erkend',
+    });
+  });
+
+  it('SubmitConfirmed maps Submitting to Submitted', () => {
+    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    expect(reduce(submitting, { tag: 'SubmitConfirmed' }).tag).toBe('Submitted');
+  });
+
+  it('SubmitFailed maps Submitting to Failed with the error', () => {
+    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const failed = reduce(submitting, { tag: 'SubmitFailed', error: 'boom' });
+    expect(failed).toMatchObject({ tag: 'Failed', error: 'boom' });
+  });
+
+  it('Retry re-submits a failure', () => {
+    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    const failed = reduce(submitting, { tag: 'SubmitFailed', error: 'boom' });
+    expect(reduce(failed, { tag: 'Retry' }).tag).toBe('Submitting');
+  });
+
+  it('Reset returns to the initial editing state', () => {
+    const submitting = reduce(editingWith('Goedkeuren'), { tag: 'Submit' });
+    expect(reduce(submitting, { tag: 'Reset' })).toEqual(initial);
+  });
+});