feat: Phase 1 FDA host-operator Role and railiance01 pilot (WP-0009 T02–T07)

Lock DEC-FDA-001 working defaults; add roles/host-operator package with
OS/security and load protocols; scaffold eng-coulomb-railiance01-ho-001
with bound agent, vault, ramp checklists, and Kai quote/ledger.

engagements/pilots/eng-coulomb-railiance01-ho-001/ENGAGEMENT.yaml

@@ -0,0 +1,51 @@
+apiVersion: kaizen.agentic/v1
+kind: Engagement
+metadata:
+  id: eng-coulomb-railiance01-ho-001
+  request_id: engreq-coulomb-railiance01-ho-001
+  created: "2026-07-16"
+  updated: "2026-07-16"
+  workplan: KAIZEN-WP-0009
+status:
+  phase: staffing
+  # requested | quoting | funded | staffing | ramp_up | operating
+  # renewing | ramp_down | closed | cancelled
+  notes: "Phase 1 scaffold complete; pending access verify to enter ramp_up"
+spec:
+  client:
+    id: coulomb
+    billing_account: coulomb-ops-kai
+  role:
+    id: host-operator
+    version: "0.1.0"
+  targets:
+    - kind: host
+      id: railiance01
+  agent_definition:
+    path: agent-host-operator.md
+    derived_from: roles/host-operator/agent-definition.md
+    base_craft: agents/agent-sys-medic.md
+  vault:
+    root: vault/
+    memory: vault/memory.md
+  schedule:
+    path: schedule.yml
+  checklists:
+    ramp_up: checklists/ramp-up-status.md
+    ramp_down: checklists/ramp-down-status.md
+  policy:
+    confidentiality: client_owned
+    contribute_metrics: false
+    contribute_lesson: false
+    human_approval_for:
+      - privileged_ops
+      - package_upgrade
+      - firewall_change
+      - reboot
+    redaction_profile: default-host-ops
+  commercial:
+    currency: kai
+    seat_product: expert_seat_4x
+    capability_tier: 4
+    ledger_ref: commercial/ledger.jsonl
+    quote_ref: commercial/quote.yaml