T-0.4 Chainsaw conformance harness + coverage + behavior scaffolds (R-TEST-01..06)

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

conformance/.gitignore

@@ -0,0 +1,7 @@
+# Generated artifacts — regenerated by run.sh on every run; never committed.
+# CI collects these from the workspace / results PVC; they are inputs to the gate,
+# not source. (Root .gitignore also covers *.junit.xml and coverage/.)
+_artifacts/
+
+# Downloaded pinned tool binaries (run.sh may fetch chainsaw/kubectl here).
+.bin/