Add multi-site Caddy helpers and document usage

- add startup/shutdown scripts that render a Caddyfile from JSON config and run health checks

- add Python utilities and a sample sites.json for declarative multi-site configuration

- document the workflow and ignore generated Caddy state artifacts

- normalize double-quote style across challenge workflow controllers, nodes, and tests

api/services/challenge_service.py

@@ -60,5 +60,3 @@ class ChallengeService:
         sess.add(attempt)
         sess.commit()
         return attempt
-
-

api/services/red_blue_service.py

@@ -87,5 +87,3 @@ class RedBlueService:
         sess.add(pairing)
         sess.commit()
         return pairing
-
-