Self-host compose stack and production stability fixes

.env.example

@@ -1,8 +1,7 @@
-NODE_ENV=production
 PORT=3000
 
 # App auth / storage / database
-DATABASE_URL=mysql://user:password@127.0.0.1:4000/tennis_training_hub
+DATABASE_URL=mysql://tennis:replace-with-db-password@db:3306/tennis_training_hub
 JWT_SECRET=replace-with-strong-secret
 VITE_APP_ID=tennis-training-hub
 OAUTH_SERVER_URL=
@@ -12,6 +11,13 @@ BUILT_IN_FORGE_API_KEY=
 VITE_OAUTH_PORTAL_URL=
 VITE_FRONTEND_FORGE_API_URL=
 VITE_FRONTEND_FORGE_API_KEY=
+LOCAL_STORAGE_DIR=/data/app/storage
+
+# Compose MySQL
+MYSQL_DATABASE=tennis_training_hub
+MYSQL_USER=tennis
+MYSQL_PASSWORD=replace-with-db-password
+MYSQL_ROOT_PASSWORD=replace-with-root-password
 
 # LLM chat completion endpoint
 LLM_API_URL=https://one.hao.work/v1/chat/completions