fix(ci): make pr-ci-sweeper clock injectable so lookback fixtures cannot rot

scripts/github/pr-ci-sweeper.mjs

@@ -131,13 +131,21 @@ async function reopenWithRetry({ github, core, owner, repo, pullNumber }) {
   return false;
 }
 
-export async function runPrCiSweeper({ github, context, core, dryRun = false, appSlug = "" }) {
+export async function runPrCiSweeper({
+  github,
+  context,
+  core,
+  dryRun = false,
+  appSlug = "",
+  // Injectable clock: fixture-based tests pin a fixed instant so lookback
+  // classification cannot rot as wall-clock time passes the fixture dates.
+  now = Date.now(),
+}) {
   const sweeperLogins = new Set(KNOWN_SWEEPER_LOGINS);
   if (appSlug) {
     sweeperLogins.add(`${appSlug}[bot]`);
   }
   const { owner, repo } = context.repo;
-  const now = Date.now();
   const results = [];
   let refires = 0;
   const openPrs = await github.paginate(github.rest.pulls.list, {