fix(companion): accept view:null in turn schema (rail sends null when no active entity)

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

tests/api/companion.test.js

@@ -45,7 +45,7 @@ describe('companion API', () => {
 
   it('POST /turn streams SSE events and persists messages', async () => {
     const res = await auth(request(app).post(`/api/spaces/${spaceId}/companion/turn`))
-      .send({ text: 'make a task to validate the CSV' });
+      .send({ text: 'make a task to validate the CSV', view: null }); // rail sends view:null
 
     expect(res.status).toBe(200);
     expect(res.headers['content-type']).toMatch(/text\/event-stream/);