feat(docker): add webhook to auto-redeploy on master commit, remove old docker-related files

.env.docker.example

@@ -1,4 +1,4 @@
-# Le Tribunal — Docker deployment with managed Supabase
+# Le Tribunal — Docker deployment
 
 # --- Domain ---
 APP_DOMAIN=acropole.alxczl.fr
@@ -6,7 +6,6 @@ APP_DOMAIN=acropole.alxczl.fr
 # --- Traefik ---
 TRAEFIK_NETWORK=proxy
 
-# --- Supabase (managed) ---
-# From your Supabase project: Settings -> API
-SUPABASE_URL=
-SUPABASE_ANON_KEY=
+# --- Webhook (auto-deploy on push) ---
+# openssl rand -hex 16
+WEBHOOK_SECRET=