Fix SonarQube issues, store sessions in Redis, use direct analytics URLs

- ApiSandboxController: reduce scan() returns from 4 to 3 via ternary
- ApiDocController: add MIME_JSON constant, extract buildInsomniaRequest()
  and buildInsomniaBody() to reduce cognitive complexity
- Store sessions in Redis to fix SSO disconnect with 2 PHP replicas
  (round-robin load balancing caused session loss on filesystem storage)
- Configure session cookie: 24h lifetime, secure auto, samesite lax
- Replace Caddy analytics proxies (/stats/*, /assets/perf.js, /sperf)
  with direct URLs to tools-security.esy-web.dev and cloudflareinsights.com
- Update JS tests for new direct analytics URLs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ansible/caddy.j2

@@ -9,27 +9,6 @@ ticket.e-cosplay.fr {
         file_server
     }
 
-    handle_path /stats/* {
-        rewrite * {uri}
-        reverse_proxy https://tools-security.esy-web.dev {
-            header_up Host tools-security.esy-web.dev
-        }
-    }
-
-    handle /assets/perf.js {
-        rewrite * /beacon.min.js
-        reverse_proxy https://static.cloudflareinsights.com {
-            header_up Host static.cloudflareinsights.com
-        }
-    }
-
-    handle_path /sperf {
-        rewrite * /cdn-cgi/rum
-        reverse_proxy https://cloudflareinsights.com {
-            header_up Host cloudflareinsights.com
-        }
-    }
-
     @maintenance file /var/www/e-ticket/public/.update
     handle @maintenance {
         root * /var/www/e-ticket/public