feat: harness VM stack (runner, measure-db, blackbox, Alloy, k6) and the 12 scenarios

Experiment design 5 and 7 for the harness VM (10.20.0.11): vm/harness/apply.sh pulls the secrets from Secret Manager,
compose runs runner:de076a7, measure-db, blackbox, Alloy (probe_success -> Mimir) and k6 under the campaign profile.
Scenario files C-K1..X-M2 are loaded by the runner. Harness ClusterRole gains replicasets get/list for rollout undo.

vm/harness/scenarios/C-K3.yaml

@@ -0,0 +1,15 @@
+# design 7 C-K3: known signature, container. Out-of-Git change (scale api to 1); Argo CD selfHeal restores replicas 3.
+id: C-K3
+path: known
+asset: container
+expected_layer: 1
+ground_truth_label: gitops_drift
+ground_truth_action: none
+description: harness scales deployment/api to 1 outside Git
+inject:
+  method: kubectl_scale
+  namespace: demo
+  deployment: api
+  replicas: 1
+revert:
+  method: none