feat(orders): a fifth verdict, 'bad', between ok and never again

The jump from "OK" to "Never again" is too big and most
disappointments live in the gap (user, 2026-07-28) — so a merely poor
meal either flattered itself as OK or got blacklisted.

Only 'never' raises the warning on a future order. A blacklist that fires
for every mediocre delivery is one nobody reads, so 'bad' records the
disappointment without triggering the alarm. Both set order_again = false
— you would not choose either again — and that split between "would I
order it" and "warn me about it" is the point of the extra level.

Migration widens the CHECK; nothing is removed, so no existing row needs
mapping.

src/__tests__/integration/order-reviews.test.ts

@@ -92,6 +92,25 @@ describe("order verdicts — one per person", () => {
     expect(body.reviews[0].order_again).toBe(false);
     body = await (await PUT(req({ rating: "ok" }), params(txnId))).json();
     expect(body.reviews[0].order_again).toBe(true);
+    // "bad" is also a no — you would not choose it again.
+    body = await (await PUT(req({ rating: "bad" }), params(txnId))).json();
+    expect(body.reviews[0].order_again).toBe(false);
+  });
+
+  it("only `never` raises the warning, not `bad`", async () => {
+    // The boundary the five-level scale exists for. A blacklist that fires for
+    // every mediocre meal is one nobody reads, so "bad" records the
+    // disappointment without triggering the alarm.
+    const older = await seedOrder("Thai Palace", "2026-06-01");
+    await PUT(req({ participant_id: ownerId, rating: "bad" }), params(older));
+
+    let body = await (await GET(req(), params(txnId))).json();
+    expect(body.merchant.counts.bad).toBe(1);
+    expect(body.merchant.warn).toBe(false);
+
+    await PUT(req({ participant_id: ownerId, rating: "never" }), params(older));
+    body = await (await GET(req(), params(txnId))).json();
+    expect(body.merchant.warn).toBe(true);
   });
 });