feat(intake): record whether the submitter asked for a cut-out (#281)

The public intake POST now reads a `removeBackground` multipart field and stores it on the new `item_drafts.remove_background` column. The checkbox on the submission page is ticked by default, so a client that sends nothing gets `true` — only the exact string `'false'` opts out, so a stray or unexpected value is treated as consent rather than a silent refusal.

The GET now also reports `backgroundRemoval: isRembgConfigured()` alongside the label, so the submission page knows up front whether the feature exists in this environment at all. Neither handler calls the sidecar or the AI — this task only records intent for the drafting worker to act on later, and the existing ordering of `requireUsableLink` and `requireCapacity` ahead of `uploadImages` is unchanged.

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

backend/tests/integration/intake.integration.test.ts

@@ -39,6 +39,13 @@ async function issueLink(label = 'Sarah', maxSubmissions?: number | null): Promi
   return res.body.token as string;
 }
 
+/** A submission with optional extra multipart fields beside the photo. */
+function postPhoto(token: string, fields: Record<string, string> = {}) {
+  const req = request(app).post(`/api/intake/${token}`);
+  for (const [name, value] of Object.entries(fields)) void req.field(name, value);
+  return req.attach('images', PNG, 'a.png');
+}
+
 describe('checking a link before showing the form', () => {
   it('names the link so the page can greet the sender', async () => {
     const token = await issueLink('Sarah');
@@ -207,3 +214,62 @@ describe('a submitted item does not reach the storefront', () => {
     expect(res.body).toHaveLength(0);
   });
 });
+
+describe('the background-removal intent', () => {
+  // Ticked by default on the page, so absent means yes. An older client or a
+  // curl call then behaves like the current default rather than silently
+  // opting out of something every other submission gets.
+  it('defaults to true when the field is not sent', async () => {
+    const token = await issueLink();
+    await postPhoto(token);
+
+    const { rows } = await pool.query<{ remove_background: boolean }>(
+      `SELECT remove_background FROM item_drafts ORDER BY id DESC LIMIT 1`
+    );
+    expect(rows[0]?.remove_background).toBe(true);
+  });
+
+  it('records a submitter who unticked it', async () => {
+    const token = await issueLink();
+    await postPhoto(token, { removeBackground: 'false' });
+
+    const { rows } = await pool.query<{ remove_background: boolean }>(
+      `SELECT remove_background FROM item_drafts ORDER BY id DESC LIMIT 1`
+    );
+    expect(rows[0]?.remove_background).toBe(false);
+  });
+
+  // Only the exact string opts out. A stray value is not a considered "no",
+  // and reading it as one would quietly deny somebody something they asked for.
+  it('treats anything other than "false" as consent', async () => {
+    const token = await issueLink();
+    await postPhoto(token, { removeBackground: 'no' });
+
+    const { rows } = await pool.query<{ remove_background: boolean }>(
+      `SELECT remove_background FROM item_drafts ORDER BY id DESC LIMIT 1`
+    );
+    expect(rows[0]?.remove_background).toBe(true);
+  });
+});
+
+describe('what the submission page is told', () => {
+  it('says the feature is off when there is no sidecar', async () => {
+    delete process.env.REMBG_URL;
+    const token = await issueLink();
+
+    const res = await request(app).get(`/api/intake/${token}`);
+
+    expect(res.status).toBe(200);
+    expect(res.body.backgroundRemoval).toBe(false);
+  });
+
+  it('says it is on when there is one', async () => {
+    process.env.REMBG_URL = 'http://rembg-syn:7000';
+    const token = await issueLink();
+
+    const res = await request(app).get(`/api/intake/${token}`);
+
+    expect(res.body.backgroundRemoval).toBe(true);
+    delete process.env.REMBG_URL;
+  });
+});