remove legacy backend stack and stale deployment docs after rebuild

.env.example

@@ -1,28 +1,10 @@
-# PostgreSQL
-DATABASE_URL=postgres://postgres:postgres@localhost:5432/fiscal
-POSTGRES_USER=postgres
-POSTGRES_PASSWORD=postgres
-POSTGRES_DB=fiscal
-POSTGRES_HOST=localhost
-
-# API service
-PORT=3001
-NODE_ENV=development
-FRONTEND_URL=http://localhost:3000
-BETTER_AUTH_SECRET=replace-with-strong-random-secret
-BETTER_AUTH_BASE_URL=http://localhost:3001
-SEC_USER_AGENT=Fiscal Clone <support@example.com>
-
-# Frontend
-NEXT_PUBLIC_API_URL=http://localhost:3001
-# In Coolify this must be the public backend URL (e.g. https://api.fiscal.example.com)
+# Optional API override. Leave empty to use same-origin internal API routes.
+NEXT_PUBLIC_API_URL=
 
 # OpenClaw / ZeroClaw (OpenAI-compatible)
 OPENCLAW_BASE_URL=http://localhost:4000
 OPENCLAW_API_KEY=replace-with-your-agent-key
 OPENCLAW_MODEL=zeroclaw
 
-# Queue tuning
-TASK_HEARTBEAT_SECONDS=15
-TASK_STALE_SECONDS=120
-TASK_MAX_ATTEMPTS=3
+# SEC API etiquette
+SEC_USER_AGENT=Fiscal Clone <support@fiscal.local>