[constants] Refactor 1000 to MS_PER_SECOND

- Extracted MS_PER_SECOND to src/constants.mjs
- Replaced literal 1000 in src/relay-health.mjs, src/utils.mjs, src/lib.mjs, src/lock-ops.mjs
- Updated test/scheduler-lock-failure-schema.contract.test.mjs to copy constants.mjs
- Added task log and artifacts

Co-authored-by: PR0M3TH3AN <[email protected]>

src/utils.mjs

@@ -1,11 +1,12 @@
 import fs from 'node:fs';
+import { MS_PER_SECOND } from './constants.mjs';
 
 export function todayDateStr() {
   return new Date().toISOString().slice(0, 10);
 }
 
 export function nowUnix() {
-  return Math.floor(Date.now() / 1000);
+  return Math.floor(Date.now() / MS_PER_SECOND);
 }
 
 export function getIsoWeekStr(dateInput) {