Add cookie consent widget with analytics tunnel bypass for adblock

- Create cookie-consent.js module: banner show/hide, cookie management, conditional analytics loading
- Add cookie banner widget in base.html.twig (accept/refuse buttons)
- Analytics script loaded from /stats/ tunnel (bypass adblock) with data-host-url
- Add Caddy reverse proxy tunnel /stats/* -> tools-security.esy-web.dev
- Add tools-security.esy-web.dev to CSP connect-src
- Add 9 JS tests for cookie consent
- Revert manual composer.json edit for amazon-mailer (needs composer require)

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

composer.json

@@ -22,7 +22,6 @@
         "phpstan/phpdoc-parser": "^2.3",
         "stevenmaguire/oauth2-keycloak": "^6.1",
         "stripe/stripe-php": "*",
-        "symfony/amazon-mailer": "8.0.*",
         "symfony/asset": "8.0.*",
         "symfony/console": "8.0.*",
         "symfony/doctrine-messenger": "8.0.*",