feat(pb): add stock_purchases.additional_attachments file field (migration)

Co-authored-by: Orca <help@stably.ai>

scripts/migrations/2026-08-06-stock-purchases-additional-attachments.ts

@@ -0,0 +1,68 @@
+// scripts/migrations/2026-08-06-stock-purchases-additional-attachments.ts
+//
+// One-shot schema migration: add an `additional_attachments` file
+// field to the `stock_purchases` collection. Mirrors the
+// `purchase_orders.additional_attachments` field added by
+// `2026-07-09-po-additional-attachments.ts`.
+//
+// Why this exists: stock POs didn't have a place to attach supplier
+// invoices, packing slips, or photos of damaged stock. The
+// `documents` / `documents_history` fields are the versioned-PDF
+// ledger for the operator-generated PO PDF, so we add a sibling
+// field rather than reusing `documents`.
+//
+// The MCP `stock_purchases.add_attachment` tool, the REST upload /
+// delete routes under `/api/v1/stock-purchases/[id]/attachments/...`,
+// and the AttachmentsCard on `/stock-orders/[id]` all depend on this
+// field existing in PB.
+//
+// Idempotent: re-running is a no-op when the field is already present.
+
+import { getAdminPocketBase } from "@/lib/server/pocketbase-admin";
+
+const COLLECTION_NAME = "stock_purchases";
+const FIELD_NAME = "additional_attachments";
+
+async function main() {
+  const pb = await getAdminPocketBase();
+
+  const collection = await pb.collections.getOne(COLLECTION_NAME);
+  const existing = (collection.fields ?? []) as Array<{ name: string }>;
+  if (existing.some((f) => f.name === FIELD_NAME)) {
+    console.log(
+      `[stock-purchases-additional-attachments] field already present on ${COLLECTION_NAME}`,
+    );
+    return;
+  }
+
+  // PB file-field convention: `maxSelect: 0` means "no cap" (the
+  // route enforces 25 MB per file via MAX_BYTES). Matches the PO
+  // migration exactly.
+  const newField = {
+    name: FIELD_NAME,
+    type: "file",
+    required: false,
+    presentable: false,
+    protected: false,
+    maxSelect: 0,
+    maxSize: 0,
+    mimeTypes: null,
+    thumbs: null,
+  };
+
+  await pb.collections.update(collection.id, {
+    fields: [...existing, newField],
+  });
+
+  console.log(
+    `[stock-purchases-additional-attachments] created field on ${COLLECTION_NAME} (file, multi, any mime)`,
+  );
+}
+
+main().catch((err) => {
+  console.error(
+    "[stock-purchases-additional-attachments] failed:",
+    err,
+  );
+  process.exit(1);
+});