feat(ocr): discard abandoned capture batches

A bad scan, the wrong PDFs or a duplicate upload used to leave a batch
sitting in READY_FOR_REVIEW forever, because the only exits were confirm
(posts to the books) or rejecting every page one at a time. Add a
DISCARDED terminal status to both OCR domains and a single endpoint per
domain that rejects every page still pending in one shot.

Discarding is refused once anything has landed: statements once a page is
POSTED, policies once a page is APPLIED. Those batches did real work and
have to be settled page by page.

- POST /statements/batches/:id/discard
- POST /policy-ocr/batches/:id/discard
- shared DiscardBatchCard on both review screens, gated the same way

apps/api/src/statements/statements.service.ts

@@ -342,10 +342,54 @@ export class StatementsService {
     if (doc.status === "POSTED") {
       throw new BadRequestException("Este documento ya fue registrado.");
     }
-    return this.prisma.statementDocument.update({
+    const updated = await this.prisma.statementDocument.update({
       where: { id },
       data: { status: "REJECTED", reviewedById, reviewedAt: new Date() },
     });
+    // Rejecting the last open page settles the batch just as posting it would
+    // — without this, a fully-rejected batch sat in READY_FOR_REVIEW forever
+    // because only confirmBatch() ever closed one.
+    await this.closeIfDone(doc.batchId);
+    return updated;
+  }
+
+  /**
+   * Throw away a whole batch that is pending review: every page that has not
+   * been posted is marked REJECTED and the batch itself becomes DISCARDED.
+   *
+   * Refuses once any page is POSTED — those pages already wrote ledger rows
+   * against a check, and a "discarded" label on the batch would leave those
+   * charges unexplained. Reject the remaining pages individually instead.
+   */
+  async discardBatch(batchId: string, reviewedById: string) {
+    const batch = await this.prisma.statementBatch.findUnique({
+      where: { id: batchId },
+    });
+    if (!batch) throw new NotFoundException("Lote no encontrado.");
+    if (batch.status === "DISCARDED") {
+      throw new BadRequestException("Este lote ya fue descartado.");
+    }
+
+    const posted = await this.prisma.statementDocument.count({
+      where: { batchId, status: "POSTED" },
+    });
+    if (posted > 0) {
+      throw new BadRequestException(
+        `No se puede descartar: ${posted} página(s) ya se registraron en el estado de cuenta.`,
+      );
+    }
+
+    const { count } = await this.prisma.statementDocument.updateMany({
+      where: { batchId, status: { notIn: ["POSTED", "REJECTED"] } },
+      data: { status: "REJECTED", reviewedById, reviewedAt: new Date() },
+    });
+
+    await this.prisma.statementBatch.update({
+      where: { id: batchId },
+      data: { status: "DISCARDED", completedAt: new Date() },
+    });
+
+    return { batchId, rejected: count };
   }
 
   // --- posting --------------------------------------------------------------
@@ -461,8 +505,10 @@ export class StatementsService {
       where: { batchId, status: { in: OPEN } },
     });
     if (open === 0) {
-      await this.prisma.statementBatch.update({
-        where: { id: batchId },
+      await this.prisma.statementBatch.updateMany({
+        // `updateMany` + a status filter so a discarded batch is never quietly
+        // relabelled COMPLETED by a late reject on one of its pages.
+        where: { id: batchId, status: { not: "DISCARDED" } },
         data: { status: "COMPLETED", completedAt: new Date() },
       });
     }