Add isolated development environment

README.md

@@ -74,9 +74,39 @@ Git status:
 
 pct exec 306 -- bash -lc "cd /opt/minerops && git status --short"
 
+## Safe local development
+
+Development uses a separate Compose project, database volume, Redis volume, and
+localhost-only backend port. It does not reuse the production `.env` file.
+Scheduled scanning and real miner power/reboot controls are disabled.
+
+First-time setup:
+
+```bash
+./scripts/dev-env-init.sh
+docker compose --env-file .env.dev -f compose.dev.yaml up -d --build
+```
+
+Verify the environment:
+
+```bash
+docker compose --env-file .env.dev -f compose.dev.yaml ps
+curl --fail --silent http://127.0.0.1:18000/api/health
+```
+
+Stop development services without deleting their data:
+
+```bash
+docker compose --env-file .env.dev -f compose.dev.yaml down
+```
+
+The generated `.env.dev` file is mode `0600` and ignored by Git. To use a
+different local port, change `MINEROPS_DEV_PORT` in `.env.dev`.
+
 ## Safety notes
 
 - Do not commit .env.
 - Do not commit backups, logs, database dumps, imports, or runtime data.
+- Do not enable scanning or real miner controls in the development environment.
 - Check /system-health after major changes.
 - Commit and push after each stable working change.