Harden Swapter timestamp parsing and add changelog entry

Use smartIsoDateFromTimestamp for the Swapter time.create field so the
transform produces correct dates whether the partner sends Unix seconds
or milliseconds, matching the other reports-server partner plugins. Add
the missing CHANGELOG entry for the Swapter integration.

Claude-Session: https://claude.ai/code/session_01STk8j8NcL2LgiuXRxirVn6

Author: j0ntz

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+- added: Add Swapter reporting
 - changed: Add index for orderId
 - changed: Add EVM chainId, pluginId, and tokenId fields to StandardTx
 - changed: Update Lifi to provide chainId, pluginId, and tokenId

src/partners/swapter.ts

@@ -16,7 +16,7 @@ import {
   StandardTx,
   Status
 } from '../types'
-import { datelog, retryFetch, snooze } from '../util'
+import { datelog, retryFetch, smartIsoDateFromTimestamp, snooze } from '../util'
 
 const asSwapterStatus = asMaybe(
   asValue(
@@ -198,8 +198,7 @@ export const swapter: PartnerPlugin = {
 export function processSwapterTx(rawTx: unknown): StandardTx {
   const tx: SwapterTx = asSwapterTx(rawTx)
 
-  const date = new Date(tx.time.create)
-  const timestamp = tx.time.create / 1000
+  const { timestamp, isoDate } = smartIsoDateFromTimestamp(tx.time.create)
 
   return {
     status: statusMap[tx.info.status],
@@ -227,7 +226,7 @@ export function processSwapterTx(rawTx: unknown): StandardTx {
     payoutAmount: tx.withdraw.amount,
 
     timestamp,
-    isoDate: date.toISOString(),
+    isoDate,
 
     usdValue: tx.info.equivalent > 0 ? tx.info.equivalent : -1,