Add runbook pack spec, validator, legacy launcher, and workplans RBT-WP-0002..0006

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

Assistant: claude-code
Assistant-Model: sonnet
Assistant-Process: 295952@bnt-lap001
Assistant-Session: e93f64ad-516c-46eb-9666-aad8d300c477

runbooks/example-hello/pack.yaml

@@ -0,0 +1,25 @@
+spec: runbook-pack/v0.1
+id: rtut.example-hello
+title: Example - check a host answers
+owner: runbook-tutorials
+outcome: You have proven a host answers on the network.
+exercise_status: unexercised
+engine: native
+parameters:
+  - {id: host, label: Host name, type: string, default: localhost, pattern: "[a-zA-Z0-9.-]+"}
+  - {id: count, label: Ping count, type: int, default: 1}
+prerequisites:
+  - {text: A shell with ping installed, owner: workstation}
+steps:
+  - id: ping
+    title: Ping the host
+    owner: workstation
+    command: ping -c {{count}} {{host}}
+    verify:
+      done_when: ping reports 0% packet loss
+      command: ping -c {{count}} {{host}}
+      expect: exit-0
+threat_checks:
+  - Do not paste credentials into any parameter; parameters are never secret.
+ownership:
+  - {concern: The host itself, owner: whoever runs it}