M2: hello-world .drone.yml (exec) for cc-ci self-test

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.drone.yml

@@ -0,0 +1,16 @@
+---
+kind: pipeline
+type: exec
+name: self-test
+
+platform:
+  os: linux
+  arch: amd64
+
+steps:
+  - name: hello
+    commands:
+      - echo "cc-ci self-test on the exec runner"
+      - whoami
+      - abra --version
+      - docker info --format 'swarm={{.Swarm.LocalNodeState}}'