Implement UP_STOP_ON_FAIL option to manage GPU state on installation failure

- Added a new configuration option `UP_STOP_ON_FAIL` to control whether the GPU should be stopped automatically if the `up` command fails, enhancing user control over resource management.
- Updated the CLI to include a `--keep-on-fail` flag, allowing users to prevent GPU shutdown during installation errors.
- Enhanced the installation scripts and documentation to reflect these changes, providing clearer guidance on the new behavior and configuration options.
- Improved error handling in the CLI to ensure proper cleanup of resources in case of failure, preventing unexpected billing for unused GPU resources.

env.example

@@ -48,6 +48,7 @@ LLAMACPP_LOCAL_PORT=17812
 # LLAMACPP_MODELS_MANIFEST=
 # Pin / тонкая настройка LLM (несecреты; удобнее в gpu-rent.vars — см. кейсы A–H):
 # LLAMACPP_TAG=b10545
+# LLAMACPP_BACKEND=auto
 # LLAMACPP_BUILD_CUDA=1
 # LLAMACPP_FORCE_REINSTALL=1
 # LLAMACPP_ASSET_URL=
@@ -77,6 +78,8 @@ IDLE_GRACE_MINUTES=90
 # LOCAL_WATCHDOG_GRACE_MINUTES=10
 PULL_OUTPUT=false
 NOTIFY_READY=true
+# При падении install/up гасить compute (диски оставить). Отключить: false или up --keep-on-fail
+# UP_STOP_ON_FAIL=true
 # Статический API-ключ панели (X-Token) — только для баланса, не для OpenStack:
 # SELECTEL_API_TOKEN=
 # Уведомления о списании (local-watchdog tick), шаг с момента up: