Document env vars and remove theme collapse button

- Expand .env.example with full runtime, cache, Docker, and AI keys
- Add deployment secrets to .gitignore (docker-compose/.env,
  docker/.registry.env)
- Remove VIMEO_ACCESS_TOKEN from compose files; add OAuth redirect URIs
- Load registry credentials from .registry.env in deploy-img.sh
- Fail fast if protected registry lacks auth during pre-checks
- Pass DOCKER_USERNAME/PASSWORD explicitly to WSL in deploy-img.ps1
- Remove inline collapse buttons from themes-nav.component.html

.gitignore

@@ -41,3 +41,9 @@ tmp/
 # Exports Takeout extraits localement (volumineux, données personnelles)
 takeout-*/
 takeout-*.zip
+
+# Env de deploiement (contient des secrets en clair)
+docker-compose/.env
+
+# Identifiants du registre Docker (deploy-img.sh)
+docker/.registry.env