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/vault/handoff/README.md

@@ -0,0 +1,13 @@
+# Handoff pack — eng-coulomb-railiance01-ho-001
+
+Filled during **ramp-down** (RD-02).
+
+## Contents (when complete)
+
+- Summary of how railiance01 was operated under this engagement
+- Pointer to final baselines
+- Open risks → `risks.md`
+- Deferred patches and reboot debt
+- Contacts and access revocation status
+
+_Status: not started (engagement not in ramp_down)._