fix(conformance): chainsaw checks use contains(), not unsupported =~

Every chainsaw `check` used the regex operator `=~` (`($stdout =~ 'X'): true`),
which chainsaw's expression engine rejects ('SyntaxError: Unknown char: ~') — so
EVERY such test failed on the assertion even when the behavior passed. Proven with
data-survival (R-STATE-01): the Longhorn canary genuinely SURVIVED pod destruction
(DATA_SURVIVED_OK) but the test FAILED on the `=~` syntax. Converted all 10 tests to
JMESPath `contains($stdout, 'X')` (data-survival's alternation → contains||contains).
data-survival now PASSES; the other 9 (later-phase components) are syntactically fixed
for when their phases deploy.

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

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

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