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>

Makefile

@@ -5,7 +5,7 @@ SHELL := /usr/bin/env bash
 # Set this to your Gitea host if you want 'remote-set' helper
 GITEA ?= gitea.example.com
 OWNER ?= coulomb
-REPO  ?= railiance-hosts
+REPO  ?= railiance-infra
 
 # New-host defaults (can be overridden: make new-host NAME=... TYPE=...)
 TYPE  ?= cpx11