feat(orders): record what we thought of an order, per person

The ledger already knew we had ordered from a place; it did not know the
food was bad. Orders got repeated from places we disliked because nobody
remembered by the time the next one went in. That is what the receipt
ingestion was for (ING-9) and the last piece was missing: order_reviews
existed as a table with no API, no UI and no writes.

Four levels, not three. "Loved" and "liked" are both "would order again"
but only one is worth a detour, and "ok" is not a recommendation.

A verdict belongs to a person, not to an order. A shared meal produces
two opinions and they routinely disagree — that disagreement is the
useful part, and the old UNIQUE on transaction_id alone could not hold
it. Now UNIQUE (transaction_id, participant_id), and the default is the
signed-in user rather than the owner: Sonu authenticates through the same
Traefik OAuth as participant 4, so an owner default would have filed her
verdict under his name.

Per-item opinions key on the item DESCRIPTION, not its index. An index is
meaningless across orders; "the Pad Thai here is good" is the signal that
has to survive into the next order from the same merchant. Only the two
poles are offered — a per-item "ok" answers neither of the questions you
ask at order time.

Sharing is recorded as a real 50/50 split, not a decorative flag. The
split already IS the record that an order was shared, and two records of
one fact drift apart.

An ABSENT item_verdicts means "leave them alone"; an empty array clears
them. Without that distinction a note-only save silently wipes every
per-item opinion — the same shape as the bug that reset `settled` on
split rewrites, and just as invisible on screen. Mutation-tested: making
keepItems a no-op fails exactly one test.

mockDbWithPool gained queryRow. Omitting an export from the mock makes it
undefined at the call site, which fails as "not a function" and reads
like a code bug rather than a test-harness gap.

src/app/api/orders/ingest/route.ts

@@ -11,6 +11,7 @@ import {
   NotAReceiptError,
   type MessageMeta,
 } from "@/lib/order-ingestion";
+import { merchantVerdict } from "@/lib/order-reviews";
 
 /**
  * Machine ingest endpoint for order receipts.
@@ -77,6 +78,14 @@ export async function POST(req: NextRequest) {
       subject: meta.subject,
       sender: meta.sender,
     });
+    // What we said about this merchant before, so the Slack nudge can warn at
+    // the moment the order lands rather than waiting for someone to open the
+    // app. `result.transactionId` is excluded because a brand-new order has no
+    // verdict yet — anything found is genuinely a previous visit.
+    const verdict = result.skipped
+      ? null
+      : await merchantVerdict(order.merchant_name, result.transactionId);
+
     return NextResponse.json({
       kind: "order",
       order_reference: order.order_reference,
@@ -85,6 +94,11 @@ export async function POST(req: NextRequest) {
       currency: order.currency,
       is_family: order.is_family,
       ...result,
+      prior_verdict: verdict && {
+        warn: verdict.warn,
+        counts: verdict.counts,
+        last_note: verdict.history.find((h) => h.note)?.note ?? null,
+      },
     });
   } catch (e) {
     // Not a receipt: promotions, delivery updates, adjustment and refund