feat(po-attachments): add delete route for PO additional attachments

src/app/api/v1/purchase-orders/[id]/attachments/[filename]/route.ts

@@ -0,0 +1,76 @@
+import { NextRequest, NextResponse } from "next/server";
+import { getAdminPocketBase } from "@/lib/server/pocketbase-admin";
+
+/**
+ * DELETE /api/v1/purchase-orders/[id]/attachments/[filename]
+ *
+ * Remove a single additional attachment from a PO by token. The
+ * `filename` segment is the PB-stored token (the same string that
+ * appears in `additional_attachments[]`), not the operator's
+ * original filename.
+ *
+ * Response:
+ *   200 — { ok: true, attachments: [remaining tokens] }
+ *   404 — { error: "Attachment not found" }
+ *   500 — { error: "PB admin unavailable" | <message> }
+ *
+ * Note: PB doesn't have a "delete from a multi-file field" op via
+ * the SDK, so we read the array, filter out the matching token, and
+ * write the rest back. The original PB file on disk is not deleted
+ * (PB doesn't expose a per-file delete from a multi-file field) —
+ * the token is just removed from the array, so the Send PO modal
+ * stops showing it. Re-uploading creates a fresh file.
+ */
+
+export const runtime = "nodejs";
+export const dynamic = "force-dynamic";
+
+export async function DELETE(
+  _req: NextRequest,
+  { params }: { params: Promise<{ id: string; filename: string }> },
+) {
+  const { id: poId, filename: token } = await params;
+
+  let adminPb;
+  try {
+    adminPb = await getAdminPocketBase();
+  } catch {
+    return NextResponse.json(
+      { error: "PB admin unavailable" },
+      { status: 500 },
+    );
+  }
+
+  try {
+    const po = await adminPb
+      .collection("purchase_orders")
+      .getOne<{ additional_attachments?: string[] | string }>(poId, {
+        fields: "id,additional_attachments",
+      });
+
+    const raw = po?.additional_attachments ?? [];
+    const arr = Array.isArray(raw) ? raw : raw ? [raw] : [];
+
+    if (!arr.includes(token)) {
+      return NextResponse.json(
+        { error: "Attachment not found" },
+        { status: 404 },
+      );
+    }
+
+    const remaining = arr.filter((t) => t !== token);
+    await adminPb.collection("purchase_orders").update(poId, {
+      additional_attachments: remaining,
+    });
+
+    return NextResponse.json(
+      { ok: true, attachments: remaining },
+      { status: 200 },
+    );
+  } catch (err) {
+    return NextResponse.json(
+      { error: err instanceof Error ? err.message : "Delete failed" },
+      { status: 500 },
+    );
+  }
+}