feat: package lightweight deployment profile

[loonghao]

Summary

• add YAML config-file support for controller and worker with CLI/env overrides
• let the controller serve built dashboard assets via --dashboard-dir / RFARM_DASHBOARD_DIR
• add lightweight controller/worker profiles, systemd and Windows service examples, and deployment/backup/upgrade guidance

Validation

• cargo fmt --all
• $env:PYO3_PYTHON='C:\Users\hallong\AppData\Local\Programs\Python\Python312\python.exe'; cargo test --workspace
• $env:PYO3_PYTHON='C:\Users\hallong\AppData\Local\Programs\Python\Python312\python.exe'; cargo clippy --workspace --all-targets -- -D warnings
• $env:PYO3_PYTHON='C:\Users\hallong\AppData\Local\Programs\Python\Python312\python.exe'; cargo build -p renderacre-controller -p renderacre-worker
• npm ci
• npm run build
• target\debug\renderacre-controller.exe --help
• target\debug\renderacre-worker.exe --help
• controller config/dashboard runtime smoke on 127.0.0.1:17878
• powershell -ExecutionPolicy Bypass -File scripts\e2e_smoke.ps1
• git diff --check

Closes #11