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/controllers/console/challenges.py

@@ -149,5 +149,3 @@ class ChallengeDetailApi(Resource):
         db.session.delete(c)
         db.session.commit()
         return {"result": "success"}, 204
-
-

api/controllers/console/red_blue_challenges.py

@@ -142,4 +142,3 @@ class RedBluePairingsApi(Resource):
                 for r in rows
             ],
         }
-