feat(e2e): expand org pool from 6 to 12

With 6 orgs, concurrent e2e runs from multiple PRs starve each other
for test orgs, causing cancellations after the 10-minute lock timeout.
Double the pool to 12 orgs to support higher parallelism.

New orgs (halfsend-07 through halfsend-12) must be provisioned before
merging — run hack/setup-new-e2e-org.sh for each.

Signed-off-by: Robin Bender Ginn <rbenderg@redhat.com>
Assisted-by: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Ralph Bean <rbean@redhat.com>

Author: ralphbean

e2e/admin/testutil.go

@@ -56,6 +56,12 @@ var orgPool = []string{
 	"halfsend-04",
 	"halfsend-05",
 	"halfsend-06",
+	"halfsend-07",
+	"halfsend-08",
+	"halfsend-09",
+	"halfsend-10",
+	"halfsend-11",
+	"halfsend-12",
 }
 
 // acquireOrg scans the pool for an unlocked org and acquires its lock.