chore(rename): railiance-hosts → railiance-infra

Update all operational references to reflect the new repo name per
ADR-003 (OAS S1 Infrastructure Substrate). Historical text in ADRs
and state-hub-inbox files preserved as-is. Gitea remote URL updated
locally (Gitea repo rename is a manual step).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -20,7 +20,7 @@ First, clone this repository to your workstation:
 
 ```bash
 git clone https://<your-gitea-host>/coulomb/railliance-hosts.git
-cd railiance-hosts
+cd railiance-infra
 ```
 
 ## 📦 1. Prerequisites