fix(installer): avoid pipefail marker race

tools/verify-greenfield-execution-coverage.test.sh

@@ -2,7 +2,7 @@
 set -euo pipefail
 
 ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
-SUBJECT="$ROOT/tools/verify-greenfield-execution-coverage.sh"
+SUBJECT="${GREENFIELD_COVERAGE_SUBJECT:-$ROOT/tools/verify-greenfield-execution-coverage.sh}"
 GATE="${GREENFIELD_COVERAGE_GATE:-$ROOT/tools/verify-greenfield-execution-coverage-gate.sh}"
 WORKFLOW="$ROOT/.woodpecker/greenfield-install.yml"
 INSTALLER="${GREENFIELD_E2E_INSTALLER:-$ROOT/tools/e2e-install-test.sh}"
@@ -66,6 +66,15 @@ done
 complete_output="$(bash "$SUBJECT" check cases "$manifest" "$state_root" "$run_id")"
 grep -qF '[fixture-suite] cases_defined=3 cases_executed=3' <<<"$complete_output"
 
+# A successful early match must consume the full producer and remain green under pipefail.
+large_manifest="$TMP/large-expected.tsv"
+awk 'BEGIN {
+  print "a-target\texit\t1"
+  for (i = 0; i < 20000; i++) printf "z-case-%05d\texit\t1\n", i
+}' > "$large_manifest"
+bash "$SUBJECT" init cases "$large_manifest" "$state_root" large-set
+bash "$SUBJECT" mark cases "$large_manifest" "$state_root" large-set a-target
+
 # The production manifest, including comments, initializes and checks.
 production_manifest="$ROOT/tools/fixtures/greenfield-expected-red.tsv"
 production_arms="$ROOT/tools/fixtures/greenfield-expected-arms.txt"