fix(jobs): don't overwrite the --stop_after baseline in background-job:worker

$startTime was used for two different things:
as baseline for --stop_after and as start time of the currently running job. 
The variable was reassigned during each loop with each new job in the queue, so the baseline for --stop_after was lost and the worker never terminated.

Renaming the job variable fixes this issue.

Assisted-by: Claude:claude-opus-5

Signed-off-by: Sven Hansen <vaenda@vaenda.de>

Author: vaenda

core/Command/Background/JobWorker.php

@@ -139,9 +139,9 @@ protected function execute(InputInterface $input, OutputInterface $output): int
 			memory_reset_peak_usage();
 			$jobClassId = $this->jobClassesRegistry->getId($jobClassName);
 			$jobRunId = $this->jobRuns->started($jobClassId);
-			$startTime = microtime(true);
+			$jobStartTime = microtime(true);
 			$job->start($this->jobList);
-			$timeSpent = microtime(true) - $startTime;
+			$timeSpent = microtime(true) - $jobStartTime;
 			$jobMemoryPeak = memory_get_peak_usage();
 			// TODO Job failure will never be catched here because exceptions are catched within $job->start method
 			// The error will only be visible in server logs.