fix(conformance): block-style chainsaw checks (flow-map broke on contains comma)

My previous commit converted =~ to contains() but kept flow style
'check: { (contains($stdout, 'X')): true }' — the comma inside contains() is a
YAML flow-map separator, so 9 tests failed yamllint ('expected , or }'). Convert
those checks to block style (matching data-survival), where a comma in the key
scalar is fine. Gate PASS; data-survival still green.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

conformance/tests/meta/harness-selfcheck/chainsaw-test.yaml

@@ -50,7 +50,8 @@ spec:
               test -f _artifacts/coverage/coverage.md
               test -f _artifacts/coverage/coverage.json
               echo COVERAGE_EMITTED_OK
-            check: { (contains($stdout, 'COVERAGE_EMITTED_OK')): true }
+            check:
+              (contains($stdout, 'COVERAGE_EMITTED_OK')): true
     - name: r-test-02-reproducible
       try:
         - script:
@@ -63,7 +64,8 @@ spec:
               ./run.sh --coverage-only >/dev/null
               b=$(sha256sum _artifacts/coverage/coverage.json | awk '{print $1}')
               [ "$a" = "$b" ] && echo REPRODUCIBLE_OK
-            check: { (contains($stdout, 'REPRODUCIBLE_OK')): true }
+            check:
+              (contains($stdout, 'REPRODUCIBLE_OK')): true
     - name: r-test-01-04-every-test-is-tagged
       try:
         - script:
@@ -79,7 +81,8 @@ spec:
               assert rep["summary"]["annotation_label_mismatches"]==0, "label/annotation drift"
               print("ALL_TAGGED_OK")
               PY
-            check: { (contains($stdout, 'ALL_TAGGED_OK')): true }
+            check:
+              (contains($stdout, 'ALL_TAGGED_OK')): true
     - name: r-test-05-no-safety-critical-gaps
       try:
         - script:
@@ -96,4 +99,5 @@ spec:
               assert not gaps, f"safety-critical gaps without L3 test: {gaps}"
               print("NO_SAFETY_GAPS_OK")
               PY
-            check: { (contains($stdout, 'NO_SAFETY_GAPS_OK')): true }
+            check:
+              (contains($stdout, 'NO_SAFETY_GAPS_OK')): true