docs: add comments explaining AMEX backfill logic

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: eabdelmoneim

src/server/routes/admin/backfill.ts

@@ -4,6 +4,18 @@ import { StatusCodes } from "http-status-codes";
 import { TransactionDB } from "../../../shared/db/transactions/db";
 import { standardResponseSchema } from "../../schemas/shared-api-schemas";
 
+// SPECIAL LOGIC FOR AMEX
+// added two admin routes to backfill tx hashes to the backfill table
+// loadBackfillRoute and clearBackfillRoute
+// loadBackfillRoute is used to load tx hashes to the backfill table
+// clearBackfillRoute is used to clear the backfill table
+// these routes are used by the AMEX script to backfill tx hashes to the backfill table
+// see https://github.com/thirdweb-dev/solutions-customer-scripts/blob/main/amex/scripts/load-backfill-via-api.ts
+// loadBackfillRoute is used to load tx hashes to the backfill table
+// clearBackfillRoute is used to clear the backfill table
+// these routes are used by the AMEX script to backfill tx hashes to the backfill table
+// see https://github.com/thirdweb-dev/solutions-customer-scripts/blob/main/amex/scripts/load-backfill-via-api.ts
+
 const loadRequestBodySchema = Type.Object({
   entries: Type.Array(
     Type.Object({

src/server/routes/transaction/blockchain/get-logs.ts

@@ -160,6 +160,10 @@ export async function getTransactionLogs(fastify: FastifyInstance) {
           hash = transaction.transactionHash;
         }
 
+        // SPECIAL LOGIC FOR AMEX
+        // AMEX uses this endpoint to get logs for transactions they didn't receive webhooks for
+        // the queue ID's were cleaned out of REDIS so we backfilled tx hashes to this backfill table
+        // see https://github.com/thirdweb-dev/solutions-customer-scripts/blob/main/amex/scripts/load-backfill-via-api.ts
         // Fallback to backfill table if enabled and not found
         if (!hash && env.ENABLE_TX_BACKFILL_FALLBACK) {
           const backfillHash = await TransactionDB.getBackfillHash(queueId);