test(scheduler): SCALE-001 — assert claim cap via non-Pending count, not Running

Sprint 2's TestProcessPendingJobs_RespectsClaimLimit asserted
that exactly 3 jobs sat in JobStatusRunning after a 10-row
ProcessPendingJobs sweep with SetClaimLimit(3). The CI run
landed 'running-job count = 0; want 3.'

Root cause: the mock's ClaimPendingJobs flips Pending → Running
on the 3 claimed rows (atomic-claim semantics). processJob then
calls renewalService.ProcessRenewalJob, which fails on the
mock cert-repo's not-found error and calls failJob → which
transitions the row from Running → Failed. By the time the
test assertion runs, no row is still in Running.

The load-bearing SCALE-001 invariant is 'the cap STOPPED at 3.'
Whether the 3 claimed rows ended up Running, Failed, or
Completed is irrelevant to the cap — what matters is that 7
rows STAYED in Pending for the next tick.

Fix: count non-Pending (= claimed) and still-Pending (= 10
minus claimed) separately. Assert claimed=3 and stillPending=7.
LastClaimLimit=3 assertion (already passing in the failed run)
also stays as the seam-propagation pin.

This is a test-fix only — the SCALE-001 production behavior
landed correctly in 037876f and is proven by the CI log line
'count=3 claim_limit=3'.

internal/service/job_test.go

@@ -982,18 +982,27 @@ func TestProcessPendingJobs_RespectsClaimLimit(t *testing.T) {
 		t.Errorf("LastClaimLimit = %d; want 3 (SetClaimLimit must propagate)", jobRepo.LastClaimLimit)
 	}
 
-	// Count how many transitioned from Pending → Running via the mock's
-	// atomic-claim behaviour.
+	// The mock's ClaimPendingJobs flips claimed rows Pending → Running.
+	// processJob then runs and (since these rows reference cert IDs the
+	// mock cert-repo doesn't know about) transitions them to Failed.
+	// The load-bearing invariant for SCALE-001 is: the claim cap STOPPED
+	// at 3, so exactly 3 rows left the Pending pool and the remaining 7
+	// stayed Pending for the next tick.
 	jobRepo.mu.Lock()
 	defer jobRepo.mu.Unlock()
-	var running int
+	var stillPending, claimed int
 	for _, j := range jobRepo.Jobs {
-		if j.Status == domain.JobStatusRunning {
-			running++
+		if j.Status == domain.JobStatusPending {
+			stillPending++
+		} else {
+			claimed++
 		}
 	}
-	if running != 3 {
-		t.Errorf("running-job count = %d; want 3 (claim cap should have stopped after 3)", running)
+	if claimed != 3 {
+		t.Errorf("claimed (non-Pending) count = %d; want 3 (claim cap should have stopped after 3)", claimed)
+	}
+	if stillPending != 7 {
+		t.Errorf("still-Pending count = %d; want 7 (the cap should have left the rest untouched)", stillPending)
 	}
 }